Corrosion resistant coatings

ABSTRACT

A coating composition comprising an effective corrosion-inhibiting amount of a rare earth compound, a neutral to slightly acidic generating extender or an acidic generating extender, or combinations thereof is provided. In one embodiment, the corrosion-inhibiting components are combined with other components such as extenders, amino acids and amino acid derivatives, gelatin and gelatin derivatives, organic-based exchange resins, and combinations thereof, to enhance the corrosion resistance of the resultant coating film. The coating compositions have good adhesion to substrates such as metals, including aluminum and aluminum alloys.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. patentapplication Ser. No. 10/346,374 filed on Jan. 17, 2003, which is herebyincorporated by reference in its entirety. This application also claimsthe benefit under 35 U.S.C. 119 (e) of U.S. Provisional Application No.60/452,843 filed on Mar. 7, 2003, which is hereby incorporated byreference in its entirety.

STATEMENT OF GOVERNMENT RIGHTS

[0002] This invention was made with Government support under grantnumber AFOSRF49620-96-0140 and F33615-97-D5009 awarded by the UnitedStates Air Force. The Government may have certain rights in thisinvention.

TECHNICAL FIELD

[0003] This invention relates to coatings, and, in particular, thisinvention relates to corrosion resistant coatings.

BACKGROUND

[0004] Coatings are employed for a number of reasons. Product coatingsor industrial coatings are typically applied in a factory on a givensubstrate or product, such as appliances, automobiles, aircraft, and thelike. Many industries, including the aircraft industry, typically employcoating systems that provide both corrosion protection and enhancedperformance.

[0005] In order to improve the corrosion resistance of a metalsubstrate, corrosion inhibitive pigments or additives are typically usedin the coatings applied to the substrate. A common corrosion inhibitivepigment is strontium chromate, which provides excellent corrosionresistance. However, in recent years there has been widespread concernover the use of chromates, as they are known to be highly toxic andcarcinogenic. Furthermore, the disposal of chromate materials isbecoming increasingly difficult as municipal and government regulationsare becoming more stringent.

[0006] As a result, there have been attempts to produce corrosionresistant coatings by using environmentally acceptable corrosioninhibitive pigments or additives. However, these coatings areproblematic in that some of the pigments or additives used are eithernot compatible with the paint or cause the paint to peel off thesubstrate. Some are actually known to accelerate the corrosion process.

[0007] Thus there is a need to provide corrosion resistant coatings thatare effective, yet not based on chromates.

SUMMARY

[0008] The present invention relates to aqueous or solvent borne coatingcompositions containing rare earth compounds, such as rare earth oxides,hydroxides, mixed oxides, solid solution oxides, hydrated oxides, salts,triflates, carbonates, and complexes alone or in combination with othercomponents, having corrosion resistant properties with good adhesion tometals, including aluminum and aluminum alloys, bare and galvanizedsteel, zinc, magnesium and magnesium alloys. The invention furtherrelates to processes for preparing the coating compositions containingrare earth compounds, alone or in combination with other components.

[0009] The present invention additionally relates to aqueous or solventborne coating compositions containing one or more neutral to slightlyacidic extenders or acidic extenders, such as metal salts (e.g., metalsulfates), wherein the metal is selected from the group consisting ofcalcium, strontium, and barium, alone or in combination with othercomponents, having corrosion resistant properties with good adhesion tosubstrates such as metals, including aluminum and aluminum alloys, bareand galvanized steel, zinc, magnesium and magnesium alloys. In mostembodiments, the coating further contains a binder. The inventionfurther relates to process for preparing such coating compositionscontaining neutral to slightly acidic extenders or acidic extenders,alone or in combination with other components.

[0010] In one embodiment, a coating system comprising one or morepretreatment coatings applied to a substrate to form a pretreatedsubstrate; and an effective corrosion-inhibiting amount of a rare earthcompound, a neutral to slightly acidic generating extender and/or anacidic generating extender is provided. In one embodiment, the substrateis not pretreated. In one embodiment, the coating system includes atopcoat. In one embodiment the coating system is a resin coating. In oneembodiment, the coating system is selected from the group consisting ofa UV-coating system, electrolytic coating (e-coating) system, appliqué,powder coating system and microwave coating system. In one embodiment,the substrate is a metal substrate selected from the group consisting ofaluminum and aluminum alloys, bare and galvanized steel, zinc (intendedto include zinc alloys), magnesium and magnesium alloys, copper andbronze.

[0011] The invention additionally relates to methods of using a coatingcomposition comprising providing a substrate to be coated and coatingthe substrate with a coating composition having an effectivecorrosion-inhibiting amount of a rare earth compound, a neutral toslightly acidic generating extender or an acidic generating extender. Inone embodiment, the coating is applied by any conventional method,including, but not limited to, spraying, brushing, rolling and dipping.In one embodiment, the method further comprises applying a topcoat.

[0012] The coatings described herein have excellent corrosion resistanceperformance, while maintaining acceptable levels of paint adhesionproperties. The coating compositions are useful in many industries,including, but not limited to, the aerospace and aircraft industries.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0013] In the following detailed description, embodiments are describedin sufficient detail to enable those skilled in the art to practice theinvention. Other embodiments may be utilized and structural, logical andother changes may be made without departing from the spirit and scope ofthe present invention. The following detailed description is, therefore,not to be taken in a limiting sense. The detailed description thatfollows begins with a definition section followed by a description ofvarious embodiments of the invention. A series of examples is presentednext followed by a brief conclusion.

[0014] Definitions

[0015] As used herein, the term “substrate” refers to a structure havinga surface that can be cleaned and/or protected and/or modified toprovide unique properties. A “substrate” is not limited to anyparticular type of material, although in terms of applying a corrosioninhibiting coating, such substrates are typically metal. However,corrosion inhibiting coatings can also be applied to other substrates,such as a polymeric substrate (e.g., coated metallic substrate). Acorrosion inhibiting coating can also be applied to a compositesubstrate, such as a substrate made with carbon fibers and epoxy resin.Although a composite substrate does not corrode, a corrosion inhibitingcoating can still be used with a composite substrate to provide surfaceprotection and/or other unique properties to the substrate, although thecoating must be compatible with the substrate material. In someinstances, although the majority of the substrate can be made from acomposite material and therefore not need protection from corrosion, thepresence of other metallic surfaces within the desired coating area,e.g., metallic rivets, requires the use of a corrosion inhibitingcoating.

[0016] As used herein, the term “extender” or “extender pigment” whenused without qualification, refers to a type of pigment that istypically incorporated into a paint formulation to provide volume to thefinal resulting coating after paint curing, although it can be added forother reasons, such as to reduce cost. An extender can additionally oralternatively be an active component in making a total system morecorrosion resistant. Extenders which add volume are often referred to as“fillers” or “extenders/fillers.”

[0017] As used herein, the term “neutral to slightly acidic generatingextender”, i.e., “neutral to slightly acidic generating additive”,refers to a metal cation and a corresponding oxyanion (meaning thoseanions having an oxygen combined with one or more nonmetals). Preferredbut not required extenders are sulfur, phosphorus and siliconoxyanion-containing compounds. Of particular interest are sulfur,phosphorus and silicon oxyanion-containing salts. A neutral to slightlyacidic generating extender can be used alone or in combination withother components to generate a pH environment of between about 4 toabout 8 in a coating composition (with the pH of the coating compositiondetermined by standard methods and concentrations known to those ofskill in the art). This environment appears to help enhance and optimizetransport of the particular inhibitor species being used, from thecoating composition to areas of exposed underlying substrate. A neutralto slightly acidic generating extender can itself be acidic, neutral orbasic (e.g., Na₂HPO₄) and can also add extender properties to thecoating composition. In most instances, a neutral to slightly acidicgenerating extender does not substantially solubilize in the coatingcomposition, thereby adding volume to the composition. Examples ofneutral to slightly acidic generating extenders include, but are notlimited to, sulfates, sulfites, silicates, phosphates, phosphites,phosphonates, hydrogen sulfate, hydrogen sulfite, mono and di-hydrogenphosphate, mono and di-hydrogen phosphites and mono hydrogenphosphonate. Further examples include oxyphosphorus compounds, such ascerous phosphate and some Group IIA sulfates, such as calcium sulfate,strontium sulfate and the like. However, it is manifestly intended toinclude within this term neutral to slightly acidic generatingextenders, i.e., additives, which are substantially soluble andtherefore do not add volume to the composition. Examples include certainsulfates known in the art to not be useful in adding volume but whichhave shown surprisingly good results as corrosion inhibitors, such asmagnesium sulfate and some Group IA sulfates. The precise amount ofneutral to slightly acidic generating extender needed to generate thedesired pH in the composition will vary depending the type and amount ofbinders, solvents, pigments and other additives, including other typesof extenders present in the coating composition.

[0018] As used herein, the term “acidic generating extender”, i.e.,“acidic generating additive,” refers to a metal cation and acorresponding oxyanion (meaning those anions having an oxygen combinedwith one or more nonmetals). Preferred but not required extenders aresulfur, phosphorus and silicon oxyanion-containing compounds. Ofparticular interest are sulfur, phosphorus and siliconoxyanion-containing salts. An acidic generating extender can be usedalone or in combination with other components to generate a pHenvironment of less than between about 2 to about 4 in a coatingcomposition (with the pH of the coating composition determined bystandard methods and concentrations known to those of skill in the art).This environment appears to help enhance and optimize transport of theparticular inhibitor species being used, from the coating composition toareas of exposed underyling substrate. An acidic generating extender canitself be acidic or neutral and can also add extender properties to thecoating composition. Examples of compounds that are capable ofgenerating a pH environment of between about 2 to about 4 include, butare not limited to certain hydrogen sulfates such as calcium hydrogensulfate, calcium hydrogen phosphate and calcium di-hydrogen phosphate.Again, it is manifestly intended to include within this term acidicgenerating extenders that are substantially soluble, thereby not addingvolume to the composition. It is possible that the same compound can beproperly categorized as both an “acidic generating extender” and a“neutral to slightly acidic generating extender”, since it is capable ofgenerating either environment. One example of a compound that cangenerate either environment includes, but is not limited to, calciumhydrogen phosphate. Additionally, the precise amount of acidicgenerating extender needed to generate the desired pH in the compositionwill vary depending on the type and amount of binders, solvents,pigments and other additives present.

[0019] As used herein, the term “substantially soluble” refers to asolubility level of more than about one (1) mole per liter of water(mol/L).

[0020] As used herein, the term “not substantially soluble” refers to asolubility level of less than about one (1) mol/L.

[0021] As used herein, the term “coating” refers to a polymeric material(organic or inorganic) that can be applied either as a liquid (e.g.,paint) or solid (e.g., powder) to a substrate to form a polymeric film.Such polymeric materials include, but are not limited to, powdercoatings, paints, sealants, conducting polymers, sol gels (e.g. Boegel™made by Boeing Co. having offices in Chicago, Ill.), silicates,silicones, ziriconates, titonates, and the like. A “coating” iscomprised of a complex mixture of binders, solvents, pigments andadditives. Many coatings have one or more substances from each of thefour categories. Coating properties, such as gloss and color, arerelated to the film surface, i.e., as a two-dimensional entity. However,the bulk properties of a coating are related to its three-dimensionalstructure. Phase continuity is a volume concept, and the coatingperformance is dependent on the integrity of the binder phase.

[0022] As used herein, the term “binder” refers to any film-formingpolymeric material which can be used to make coatings. The polymericmaterial can be either organic or inorganic. Organic binders have acarbon backbone and inorganic binders generally have a siliconebackbone. Organic binders are made up of organic monomers and oligomersfrom which the binders generally derive their names. Examples of thesewould be acrylic, epoxy, urethane, melamine, and so forth. Bindersinclude epoxy-based resin binders such as a water reducibleepoxy-polyamide system (for organic polymeric materials) or nonepoxy-based resin binders such as urethanes, ureas, acrylates, alkyds,melamines, polyesters, vinyls, vinyl esters, silicones, siloxanes,silicates, sulfides, silicate polymers, epoxy novilacs, epoxy phenolics,drying oils, hydrocarbon polymers, and the like.

[0023] As used herein, the term “weight percent (wt %)” when usedwithout qualification, typically refers to the weight percent of aparticular solid component, e.g., pigment, extender, etc., as comparedwith all solid components present, excluding polymeric resins. Forexample, if the only solid component present in the coating is acorrosion-inhibiting carbon pigment, the corrosion-inhibiting carbonpigment is considered to have a wt % of 100.

[0024] As used herein, the term “mixed oxide” refers to a solid solutionof a single element having multiple oxidation states and is not intendedto refer to a mixture of oxides.

[0025] As used herein, the term “topcoat” refers to a mixture of abinder(s), which can be an organic or inorganic based polymer or a blendof polymers, typically at least one pigment, can optionally contain atleast one solvent or mixture of solvents, and can optionally contain atleast one curing agent. A topcoat is typically the coating layer in asingle or multi-layer coating system whose outer surface is exposed tothe atmosphere or environment, and its inner surface is in contact withanother coating layer or polymeric substrate. One example of a topcoatis a urethane topcoat.

[0026] As used herein, the term “self-priming topcoat”, also known as a“direct to substrate coating”, refers to a mixture of a binder(s), whichcan be an organic or inorganic based polymer or blend of polymers,typically at least one pigment, can optionally contain at least onesolvent or mixture of solvents, and can optionally contain at least onecuring agent. A self-priming topcoat is typically applied directly to asubstrate. The self-priming topcoat can optionally be applied to anorganic or inorganic polymeric coating, such as a primer or paint film.A self-priming topcoat is typically the coating layer in a single ormulti-layer coating system where the outer surface of the coating isexposed to the atmosphere or environment, and the inner surface of thecoating is typically in contact with the substrate or optional polymercoating or primer.

[0027] As used herein, the term “enhanced self-priming topcoat”, alsoreferred to herein as an “enhanced direct to substrate coating” refersto a mixture of functionalized fluorinated binders, such as afluoroethylene-alkyl vinyl ether in whole or in part with otherbinder(s), which can be an organic or inorganic based polymer or blendof polymers, typically at least one pigment, can optionally contain atleast one solvent or mixture of solvents, and can optionally contain atleast one curing agent. An enhanced self-priming topcoat is typicallyapplied directly to a substrate. The enhanced self-priming topcoat canoptionally be applied to an organic or inorganic polymeric coating, suchas a primer or paint film. An enhanced self-priming topcoat is typicallythe coating layer in a single or multi-layer coating system where theouter surface of the coating is exposed to the atmosphere orenvironment, and the inner surface of the coating is typically incontact with the substrate or optional polymer coating or primer.

[0028] The topcoat, self-priming topcoat, and enhanced self-primingtopcoat can be applied to a substrate, in either a wet or “not fullycured” condition that dries or cures over time, that is, solventevaporates. The coatings can dry or cure either naturally or byaccelerated means for example, an ultraviolet light cured system to forma film or “cured” paint. The coatings can also be applied in a semi orfully cured state, such as an adhesive.

[0029] As used herein, the terms “paint formulation”, “primerformulation”, “topcoat formulation”, “self-priming topcoat formulation”,and “enhanced self-priming topcoat formulation” refer to a list ofingredients, and/or components, and can also include a list ofinstructions for preparing and mixing together the ingredients, and/orcomponents to make a coating composition.

[0030] As used herein, the terms “mill base”, “mill base formulation”,“primer mill base”, “topcoat mill base” and “base”, “base formulation”,or “primer base”, “topcoat base”, “self-priming topcoat base”, and“enhanced direct to substrate base” refer to a portion or component of apaint formulation that comprises the majority, if not all, of thepigmentation of the coating composition, as well as some additives.

[0031] Discussion

[0032] Embodiments of the invention provide compositions for primercoatings that allow for improved corrosion resistance of metalsubstrates. In one embodiment non-primer coatings are used. In oneembodiment non-metal substrates are used. Moderate to low concentrationsof rare earth compounds, alone or in combination with other materials orcomponents, have been formulated into coating mixtures providingcorrosion resistance. Additionally provided are extenders, includingmoderate to low concentrations of neutral to slightly acidic generatingextenders and acidic generating extenders, also alone or in combinationwith other materials or components, which have been formulated intocoating mixtures providing corrosion resistance.

[0033] In one embodiment, coatings containing rare earth compounds,neutral to slightly acidic generating extenders and/or acidic generatingextenderss in varying concentrations are provided to enhance thecorrosion resistance properties of the resulting coating films. In oneembodiment, the coatings are aqueous or solvent borne coatingcompositions applied as liquids, e.g., paint. In other embodiments, thecoatings are applied in powder or paste (e.g., solgel) form. In yetother embodiments, the coating is a sealant, conducting polymer, or thelike.

[0034] Rare earth compounds useful in the present invention include, butare not limited to either anhydrous or hydrated rare earth oxides,hydroxides, mixed oxides, solid solution oxides, hydrated oxides, salts,triflates, carbonates, and complexes, such as rare earth complexes usingethylenediamine tetraacetic acid, organic-based ionic exchange resins,etc., and the like. In one embodiment, one or more rare earth compoundsare added to a coating composition. In a particular embodiment, the oneor more rare earth compounds are added in a weight percent of betweenabout 0.1 to about 90 wt % of the total amount of all pigments presentin the coating. In most embodiments, the coating contains between about0.1 to about 28 wt %, of a rare earth compound (i.e., compounds),although the invention is not so limited

[0035] The rare earth compounds useful herein can be based on any of thelanthanide series. Preferred for the practice of the invention arepraseodymium, cerium, and terbium. Particularly preferred arepraseodymium and terbium, with the most currently preferred beingpraseodymium. The oxidation state of the rare earth metal employed isimportant. For example, in the case of praseodymium, in one embodiment,praseodymium(III) is used. In another embodiment, a praseodymium(III/IV)mixture is used. In yet another embodiment, praseodymium(IV) is used.The preferred oxidation states of the rare earth compounds can also be afunction of the final coating system employed. In one embodiment, therare earth compound is a praseodymium(III) sulfate. In anotherembodiment, the rare earth compound is a praseodymium(III/IV) oxide or apraseodymium(III/IV) solid solution. In other embodiments the rare earthcompound can be a praseodymium mixed oxide, a praseodymium(III) oxide, apraseodymium(III) hydroxide, a praseodymium(IV) oxide, and anycombinations thereof, further including combinations with any otherpraseodymium or other metals.

[0036] In one embodiment the rare earth compound can be a cerium oxide,cerium hydroxide, cerium solid solution mixed oxide, cerium oxidemixture, cerium salt, neodymium oxide, neodymium hydroxide, neodymiumsolid solution mixed oxide, neodymium oxide mixture, neodymium salt,praseodymium oxide, praseodymium hydroxide, praseodymium solid solutionmixed oxide, praseodymium oxide mixture, praseodymium salt, ytterbiumoxide, ytterbium hydroxide, ytterbium solid solution mixed oxide,ytterbium oxide mixture, ytterbium salt, yttrium oxide, yttriumhydroxide, yttrium solid solution mixed oxide, yttrium oxide mixture,yttrium salt, terbium oxide, terbium hydroxide, terbium solid solutionmixed oxide, terbium oxide misture, terbium salt, and combinationsthereof.

[0037] Many rare earth compounds, alone or in combination with othermaterials, have been evaluated to date (See Examples). These compoundshave been incorporated into commercially available primer formulationsas corrosion inhibitors. Evaluation of these primer coatings containingthe rare earth compounds alone or in combination with the othermaterials in neutral salt fog environments demonstrates that thepresence of these corrosion inhibitors improves the overall corrosionresistance of the metal substrate, although it is likely any substrate,as defined herein, can benefit from application of such coatings.Similarly, it is expected that any type of coating can benefit frominclusion of rare earth compounds, alone or in combination with othercomponents. Elemental characterization of these systems suggestsleaching of the inhibitor passivates and protects the underlying metalsubstrate.

[0038] Extenders useful in the present invention include, but are notlimited to, neutral to slightly acidic generating extenders and acidicgenerating extenders. In one embodiment, one or more neutral to slightlyacidic generating extenders are used. Such extenders can be acidic,neutral or basic. Examples include, but are not limited to, sulfates,sulfonates, sulfides, sulfites, phosphates, phosphonates, phosphides,phosphates, nitrates, nitrites, nitrides, silicates and combinationsthereof. In one embodiment, one or more acidic generating extenders areused. Such extenders can be acidic or neutral. Examples include, but arenot limited to acid-modified compounds, such as acid-modifiedphosphates, phosphides, phosphates, kaolins, wallastonites, silicatesand combinations thereof.

[0039] Also useful in the present invention are conventional extendersthat can serve as a cost effective substitute for coloring pigments suchas TiO₂ and can further provide the desired pigment to binder ratios forthe primer coatings. One example of a conventional extender includes,but is not limited to, calcium carbonate. Many of these extenders appearto assist in the activation of inhibitors that can be present in theenvironment (e.g., in previously applied conversion coatings, in thepolymeric coating itself, etc.), thus enhancing the corrosion resistanceof the protective coating.

[0040] In one embodiment, the neutral to slightly acidic generatingextenders or acidic generating extenders include Group I and II metalcations. In one embodiment, the neutral to slightly acidic generatingextenders or acidic generating extenders include sulfates and phosphatesof praseodymium (such as praseodymium(III), (IV) or (III/IV) mixtures),calcium, strontium, barium and magnesium, and the natural forms of thesecompounds such as gypsum and celestite. Preferably the neutral toslightly acidic generating extenders or acidic generating extendersinclude calcium, strontium, and barium sulfates and phosphates that donot substantially solubilize in the coating composition, although theinvention is not so limited. In one embodiment, the neutral to slightlyacidic generating extenders or acidic generating extenders are selectedfrom the group that includes, but is not limited to, sulfates, includingmetal sulfates (e.g., anhydrous calcium sulfate, hydrated calciumsulfate, strontium sulfate, barium sulfate, hydrated magnesium sulfate,etc.), metal phosphates (e.g., hydrous calcium phosphate, anhydrouscalcium phosphate and mono- and di-hydrogen calcium phosphate, etc.).Again, any of the extenders described herein can be used in eithernatural (mineral) or synthetic form. The acidic generating extenders canfurther include non-sulfate, non-phosphate and non-nitrate acidicgenerating extenders, such as the Burgess extenders including calcinedclays, e.g., calcined kaolin clays, etc., made by the Burgess PigmentCo. having offices in Sandersville, Ga., and the like. However, othermetal cations and anions having the aforementioned properties can beused as neutral to slightly acidic generating extenders and acidicgenerating extenders in the coating compositions of the presentinvention, as will be understood by those of skill in the art withreference to this disclosure.

[0041] In one embodiment, one or more neutral to slightly acidicgenerating extenders and/or one or more acidic generating extenders areused. The amount of extenders used can vary considerably, because someare more efficient in the particular system being used. In oneembodiment, neutral to slightly acidic generating extenders and/oracidic generating extenders are added in a weight percent of betweenabout 1 to about 99% of the total amount of all pigments in the coating.In most embodiments the coating contains between about 30 to about 80 wt% of one or more neutral to slightly acidic generating extenders and/oracidic generating extenders. In more preferred embodiments, the coatingcontains between about 45 to 75 wt % of one or more neutral to slightlyacidic generating extenders and/or acidic generating extenders. In aparticular embodiment, between about 0.1 to about 3 wt % of one or moretypes of magnesium sulfate is used.

[0042] Several neutral to slightly acidic generating extenders andacidic generating extenders have been evaluated to date, alone or incombination with other materials (See Examples). These compounds havebeen incorporated into commercially available primer formulations ascorrosion inhibitors. Evaluation of these primer coatings containingthese extenders alone or in combination with the other materials inneutral salt fog environments demonstrates that the presence of thesecorrosion inhibitors improves the overall corrosion resistance of themetal substrate, although it is likely any substrate, as defined herein,can benefit from application of such coatings. Similarly, it is expectedthat any type of coating can benefit from inclusion of neutral toslightly acidic generating extenders and/or acidic generating extenders,alone, or in combination with other components. Elementalcharacterization of these systems suggests leaching of the inhibitorpassivates and protects the underlying metal substrate.

[0043] The “other materials or components” (i.e., “other components”)with which the corrosion inhibitors described herein can be combinedinclude, for example, binders, solvents, pigments (including soluble ornon-soluble extenders, fillers, corrosion-inhibiting pigments, and thelike), solvents, additives (e.g., curing agents, surfactants, dyes,amino acids and the like), and so forth. Note that some additives canalso properly be considered a pigment and vice versa (e.g., mattingagents). More specifically, these “other components” include, but arenot limited to, glycine, arginine, methionine, and derivatives of aminoacids, such as methionine sulfoxide, methyl sulfoxide, andiodides/iodates, gelatin and gelatin derivatives, such as animal andfish gelatins, linear and cyclic dextrins, including alpha and betacyclodextrin, triflic acid, triflates, acetates, talc, kaolin,organic-based ionic exchange resins, such as organic-based cationic andanionic exchange resins, organic-based ionic exchange resins, such asorganic-based cationic and anionic exchange resins, organic-based ionicexchange resins that have been pre-exchanged or reacted with the salts,oxides, and/or mixed oxides of rare earth material, and metal sulfates,such as sulfates of rare earth materials, magnesium sulfate, calciumsulfate (anhydrous and hydrated forms), strontium sulfate, bariumsulfate, and the like.

[0044] Corrosion co-inhibitors known in the art can also optionally beemployed in the present invention together with the rare earth compoundsand/or neutral to slightly acidic generating extenders and/or acidicgenerating extenders, and, optionally, any of the other componentsdescribed herein. Such co-inhibitors include, but are not limited to,borates, metaborates, aniline, polyaniline, and the like. Otherco-inhibitors can also be optionally employed in the present invention,such as Nalzan™ (made by NL Industries having offices in Highstown,N.J.), Busan™ (made by Buckman Laboratories having offices in MemphisTenn.), Halox™ (made by Halox Inc. having offices in Hammond, Ind.),Molywhite™ (made by Sherwin Williams Inc. having offices in Coffeyville,Kans.), and the like. It is appropriate to use only those co-inhibitorsthat are chemically compatible with the rare earth- or neutral toslightly acidic generating- or acidic generating extender-containingpaint formulation.

[0045] The various corrosion inhibitors described herein are typicallycombined with a binder, such as an organic polymer. The organic polymersuseful herein as binders include those soluble in water and thosesoluble in non-aqueous systems and powder coating systems. Polymers thatare film-forming and that crosslink upon curing are preferred. Examplesof these polymers include, but are not limited to, epoxy, urethane,urea, acrylate, alkyd, melamine, polyester, vinyl, vinyl ester,silicone, siloxane, silicate, sulfide, sulfone, epoxy novolac, epoxyphenolic, amides, drying oils, and hydrocarbon polymers.

[0046] All of the corrosion inhibitors (including co-inhibitors)discussed herein are preferably prepared in a liquid form. Thus, thebinder, such as an organic polymer, is dispersed or dissolved in anappropriate solvent, such as water or a non-aqueous solvent depending onthe nature of the polymer, and the appropriate amount of corrosioninhibitor(s) is added.

[0047] The corrosion inhibitors (including co-inhibitors) describedabove were evaluated in a polyamide/epoxy-based water reducible primerpaint formulation, although the present invention is not limited to thisspecific epoxy-based system. As such, the corrosion inhibitors can beincorporated into other primer paint formulations and employed in otherapplications where corrosion prevention is desired. Other resins caninclude, but are not limited to, e-coats, epoxy, urethane, urea,acrylate, alkyd, melamine, polyester, vinyl, vinyl ester, silicone,siloxane, silicate, sulfide, sulfone, epoxy novilac, epoxy phenolic,amides, drying oils, and hydrocarbon polymers. The preferred polymersystem is a water reducible epoxy-polyamide system. In a particularembodiment, the polyamide/epoxy-based water reducible primer paintformulation used is Deft 44GN72 manufactured by Deft Inc., havingoffices in Irvine, Calif.

[0048] Addition of about 0.1 to about 90 wt %, and preferably about 0.1to about 28 wt %, of a rare earth compound into a primer formulation (ora paint ready to apply) can be by any conventional method known in theart. Similarly, addition of about 1 to about 99 wt % and preferablyabout 45 to about 75 wt % of a neutral to slightly acidic generatingextender and/or an acidic generating extender into a primer formulation(or a paint ready to apply) can also be by any conventional method knownin the art. The primer can also include about 0.1 to about 15 wt % andpreferably about 0.5 to about 5 wt % of an organic-based ionic exchangeresin. The resin can be either cationic or anionic in nature, bothcationic and anionic can be used in the same primer formulation, and theionic exchange resin can contain rare earth compounds and/or amino acidsas pre-exchanged species prior to incorporation into a primerformulation. The primer can contain about 0.03 to about 5 wt %, andpreferably about 0.1 to about 1.2 wt %, complexing sugars and/orgelatin. The primer can also contain about 0.1 to about 5 wt % andpreferably about 0.5 to about 1.5 wt %, amino acids.

[0049] System enhancers can also be employed to enhance and optimizetransport of the particular functional species being used and ultimatelyincrease the concentration of the active inhibitor at the corrosionsites. Parameters that optimize transport include, but are not limitedto, use of conversion coatings, particle size of the pigment, dust coat,and the like.

[0050] Conversion coatings useful herein include cerium conversioncoatings (CeCC), praseodymium conversion coatings (PrCC), phosphateconversion coatings, zinc-type conversion coatings, anodized-typeconversion coatings, and chromium conversion coatings (CrCC). Theconversion coatings evaluated in conjunction with the present inventioninclude CrCC, such as those obtained using the Alodine (from Henkel) andIridite (from McDermid) processes, chromic acid anodized with chromeseal, sulfuric acid anodized with chrome seal, and the like. The age andthickness of the applied conversion coatings can further influence thecorrosion resistance of the subsequent paint coatings. It is preferredto apply the paint coating over a conversion coating which is less thanthree days old and is relatively moderate to heavy in thickness, but yetstill provides excellent adhesion to the underlying substrate.Conversion coatings that are too thick tend to result in primers withcohesive failure in the conversion coating layer. The proper conversioncoating thickness will be readily apparent to one of ordinary skill inthe art.

[0051] Additional additives and pigments can be employed to providedesired aesthetic or functional effects. If desired, the coatingcomposition can contain other components, i.e., optional materials, wellknown in the art of formulated surface coatings. These optionalmaterials would be chosen as a function of the coating system andapplication and can include flow control agents, thixotropic agents suchas bentonite clay, fillers, anti-gassing agents, organic co-solvents,catalysts, and other customary auxiliaries. These materials, if used,can constitute up to 40 percent by weight of the total weight of thecoating composition.

[0052] The coating composition of the present invention can alsooptionally contain pigments to give it color. In general, the pigment isincorporated into the coating composition in amounts of about 1 to about80 percent, usually about 1 to about 30 percent by weight based on totalweight of the coating composition. Color pigments conventionally used insurface coatings include inorganic pigments such as titanium dioxide,iron oxide, carbon black; phthalocyanine blue, and phthalocyanine green.Metallic flake pigmentation is also useful in aqueous coatingcompositions of the present invention. Suitable metallic pigmentsinclude aluminum flake, copper bronze flake, and metal oxide coatedmica. The optional pigments can comprise up to approximately 25 weightpercent of the coating composition.

[0053] The preferred concentration ranges of the components in thecoating, as well as the PVC (pigment volume concentration) of thecoating, can vary based on the resin/primer system employed. Inconcentration ranges provided, the weight percentages are based on afully catalyzed and water reduced sprayable paint Preferred for thepractice of the present invention is a coating comprising a PVC in therange of about 0.1 to about 65 wt % PVC. Particularly preferred is about10 to about 55 wt % PVC. Most preferred is an about 25 to about 45 wt %PVC.

[0054] Preferred for the practice of one embodiment of the presentinvention is a fully catalyzed and water reduced sprayable paintcomposition comprising about 0.1 to about 40 wt % Pr₆O₁₁. Particularlypreferred in this embodiment is about 0.1 to about 28 wt % Pr₆O₁₁. Mostparticularly preferred is about 0.1 to about 11 wt % Pr₆O₁₁. Otherpreferred ranges are as follows: TABLE 1A*** Rare Earth CompoundsPr₆O₁₁: Range: 0.1-90% Preferred: 0.4-28 wt % Pr₂O₃: Range: 0.1-90%Preferred: 0.4-28 wt % PrO₂: Range: 0.1-90% Preferred: 0.4-28 wt %PrO₂ + Pr₂O₃: Range: 0.1-90% Preferred: 0.4-28 wt % Tb₄O₇: Range:0.1-90% Preferred: 0.4-28 wt % CeO₂ Hydrous Range: 0.1-90% Preferred:0.4-28 wt % Pr(OH)₃: Range: 0.1-90% Preferred: 0.4-28 wt % Sm₂O₃: Range:0.1-90% Preferred: 0.4-28 wt % Yb₂O₃: Range: 0.1-90% Preferred: 0.4-28wt % Y₂O₃: Range: 0.1-90% Preferred: 0.4-28 wt % La₂O₃: Range: 0.1-90%Preferred: 0.4-28 wt % Nd₂O₃: Range: 0.1-90% Preferred: 0.4-28 wt %

[0055] Preferred for the practice of one embodiment of the presentinvention is a paint composition comprising about 1 to about 99 wt % ofa metal sulfate. Particularly preferred in this embodiment is about 30to about 80 wt % of CaSO₄.2H₂O. Most particularly preferred is about 45to about 75 wt % of CaSO₄.2H₂O. Other preferred ranges are as follows:TABLE 1B*** Neutral to Slightly Acidic Generating Extenders and AcidicGenerating Extenders Metal Sulfates: CaSO₄.2H₂O: Range: 1-99 wt %Preferred: 45-75 wt % SrSO₄: Range: 1-99 wt % Preferred: 45-75 wt %CaSO₄ Anhyd.: Range: 1-99 wt % Preferred: 45-75 wt % BaSO₄.2H₂O: Range:1-99 wt % Preferred: 45-75 wt % MgSO₄.7H₂O Range: 1-3 wt % Preferred:1.5-2.5 wt % MgSO₄.2H₂O Range: 0.1-3 wt % Preferred: 1.5-2.5 wt % PrSulfate: Range: 0.1-5 wt % Preferred: 0.5-2.5 wt % La₂(SO₄)₃.2H₂O:Range: 1-99 wt % Preferred: 45-75 wt % Li₂SO₄.2H₂O: Range: 1-99 wt %Preferred: 45-75 wt % Metal Phosphates: Ca(H₂PO₄)₂.H₂O: Range: 1-99 wt %Preferred: 45-75 wt % Ca(HPO₄).H₂O: Range: 1-99 wt % Preferred: 45-75 wt% Ca₃(PO₄)₂.H₂O: Range: 1-99 wt % Preferred: 45-75 wt % Other ExtenderTypes: CaCO₃.2H₂O Range: 3-99 wt % Preferred: 45-75 wt % Kaolin Range:3-99 wt % Preferred: 45-75 wt % Sr Carbonate: Range: 6-35% Preferred:16.1-18.8 wt % Pr Carbonate: Range: 6-35% Preferred: 16.1-18.8 wt %

[0056] For the additional materials, the following wt % ranges arepreferred: TABLE 1C*** Other Materials La₂(SO₄)₃: Range: 1-99%Preferred: 45-75 wt % Li₂SO₄ Range: 1-99% Preferred: 45-75 wt %L-Arginine: Range: 0.1-5 wt % Preferred: 0.5-1.5 wt % D,L-Arginine:Range: 0.1-5 wt % Preferred: 0.5-1.5 wt % D-Methionine: Range: 0.1-5 wt% Preferred: 0.5-1.5 wt % L-Methionine: Range: 0.1-5 wt % Preferred:0.5-1.5 wt % D,L-Methionine: Range: 0.1-5 wt % Preferred: 0.5-1.5 wt %Glycine: Range: 0.1-5 wt % Preferred: 0.5-1.5 wt % L-Cystiene: Range:0.1-5 wt % Preferred: 0.5-1.5 wt % Cystene: Range: 0.1-5 wt % Preferred:0.5-1.5 wt % Proline: Range: 0.1-5 wt % Preferred: 0.5-1.5 wt %Ethylenediaminetetraacetic acid (Free): Range: 0.1-5 wt % Preferred:0.5-1.5 wt % Ethylenediaminetetraacetic acid (Disodium salt): Range:0.1-5 wt % Preferred: 0.5-1.5 wt % D,L-Methionine Sulfoxide: Range:0.1-5 wt % Preferred: 0.5-1.5 wt % L-Methionine methylsulfonium iodide:Animal Gelatin: Range: 0.03-5 wt % Preferred: 0.1-1.2 wt % Proline ofFish Gelatin: Range: 0.03-5 wt % Preferred: 0.1-1.2 wt % Alpha or BetaCyclodextrins: Range: 0.03-5 wt % Preferred: 0.1-1.2 wt % SulfonatedCyclodextrins: Range: 0.03-5 wt % Preferred: 0.1-1.2 wt % Triflic Acid:Range: 0.1-0.5 wt % Preferred: 0.1-1.2 wt % Pr Triflate: Range: 0.4-5 wt% Preferred: 0.7-3 wt % Ce Triflate: Range: 0.4-5 wt % Preferred: 0.7-3wt % Reilex (As is): Range: 0.1-15 wt % Preferred: 0.5-5 wt % WhatmanCM23 (as is): Range: 0.1-15 wt % Preferred: 0.5-5 wt % Whatman CM23Pre-Exchanged with Range: 0.1-15 wt % Preferred: 0.5-5 wt % PraseodymiumTriflate: Whatman CM23 Pre-Exchanged with Methionine Range: 0.1-15 wt %Preferred: 0.5-5 wt % Whatman DE23 (As is): Range: 0.1-15 wt %Preferred: 0.5-5 wt % Whatman P11 (As is): Range: 0.1-15 wt % Preferred:0.5-5 wt % Whatman CM23 Pre-Exchanged with Praseodymium Range: 0.1-15 wt% Preferred: 0.5-5 wt % Salt such as a Nitrate Salt: Whatman CM23Pre-Exchanged with Range: 0.1-15 wt % Preferred: 0.5-5 wt % Cerium Saltsuch as a Nitrate Salt: Whatman CM23 Pre-Exchanged with Sulfuric Acid:Range: 0.1-15 wt % Preferred: 0.5-5 wt % Sm Acetate: Range: 0.1-5 wt %Preferred: 0.5-2.5 wt %

[0057] Any conventional method for manufacturing a paint or coating canbe used in the present invention. Examples include the use of drillpresses powered by compressed air or electricity, sand mills which useappropriate grinding media, and the like. The following is an example ofhow a primer containing any individual or combination of the aboveinhibitors can be produced:

[0058] The mill base for a polyamide/epoxy-based water reducible primerformulation can be prepared (and, in fact, was prepared for all of theExamples described herein) by dispersing one or more binders, one ormore pigments, solvent if needed, and a curing agent. The base for aself-priming topcoat composition, or enhanced self-priming topcoatcomposition can also be prepared in the same manner (and, in fact wasprepared in this manner for all of the Examples described herein). Inthis process, the base is dispersed in an appropriately sized containerat 650 rpm using a dispersion blade, such as a standard dispersion bladeand standard dispersing equipment or even a drill press, as is known inthe art. Next, under agitation at an appropriate speed, such as about600-700 rpm, coloring pigments, naturally occurring extenders, that is,minerals such as gypsum, and synthetic extenders, together with anyother corrosion inhibitors are incorporated into the coatingformulation. If an appropriate grinding media is desired, it can beadded as needed. Next, once the material is properly added to theformulation, the base is allowed to disperse for a suitable time andspeed, such as about five more minutes at 650 rpm. After this time, thedispersion speed can be increased as needed, such as to about 1600 to1640 rpm until the desired mill base pigment grind is obtained.

[0059] During dispersion at the higher speed, the temperature of themill base can be monitored and kept below the recommended temperaturesfor the ingredients and resin systems used. If it appears that the millbase temperature is close to exceeding the recommended temperatures forthe stability of the ingredients or resins, the dispersion speed can bereduced appropriately. If necessary, the dispersion process can behalted momentarily to allow proper cooling.

[0060] As will be understood by those of skill in the art with referenceto this disclosure, other steps, such as using cooling systems tominimize higher dispersion temperatures can additionally oralternatively be used. Also, as will be understood by those of skill inthe art with reference to this disclosure, the solvent employed in thepreparation of the coating system is chosen in such a manner as tofacilitate the preparation of the coating mixture, to provide suitableapplication properties, and provide and environmentally acceptablepaint.

[0061] Next, once the desired pigment particle size for the base grindis obtained, the dispersion process can be halted, and the basefiltered, if desired, to remove any undesired material from the base,such as grinding media that can optionally have been used. Next, thebalance of formula ingredients are then added in a “letdown phase”, asit is known in the art, while the pigment base or mill base is mixed. Anoptional step is to allow the base or finished paint to set for at leasttwenty-four hours prior to use, which allows the resin to wet all of thepigments.

[0062] The shelf life of the polyamide/epoxy-based water reducibleprimer formulation or the self-priming topcoat composition, or theenhanced self-priming topcoat composition prior to use is generallydictated by the time specifications provided by the supplier of theresin system.

[0063] Next, the polyamide/epoxy-based water reducible primerformulation, self-priming topcoat composition, or the enhancedself-priming topcoat composition is prepared by stirring appropriateamounts of a catalyst or activator, such as an isocyanate catalyst, intothe finished base described above. Examples of isocyanate catalysts forself-priming topcoat or enhanced self-priming topcoat formulationsinclude an isocyanate solution known as Deft 97GY088CAT available fromDeft Inc., having offices in Irvine, Calif. To ensure proper curing andcross-linking of the resulting paint film, the amount of isocyanatecatalyst added to the finished paint base can vary depending on theparticular components of the coating system, as will be understood bythose of skill in the art with reference to this disclosure.

[0064] Next, for the self-priming topcoat composition, or the enhancedself-priming topcoat composition, once the finished base and catalysthave been mixed together, the coating is ready for application to asubstrate. The substrate to be coated can be that of a fabricatedarticle, such as aircraft, automobiles, trucks, and farm equipment, forexample, further including the components and parts for these articles.

[0065] Next, for the polyamide/epoxy-based water reducible primerformulation, once the appropriate amounts of epoxy catalyst and millbase are well mixed together, the appropriate amount of water is thenslowly mixed into the primer mill base/epoxy catalyst blend and testingcan be performed. The purity and amount of water added depends on whatis recommended by the supplier of the coating system based on the sprayviscosity and final use of the coating. Since the paint formulation is awater reducible system, care needs to be taken when adding the aqueouscomponent to the epoxy catalyst/mill base blend.

[0066] The medium employed in the preparation of the coating system ofthe present invention is typically chosen in such a manner as tofacilitate the preparation of the coating mixture, and to providesuitable adhesion to the substrate. The preferred medium is water, whichincludes the preparation of water borne coatings. Other systems includesolvent-based and powder coatings.

[0067] As noted above, once the mill base/epoxy blend and appropriateamount of water are mixed together, the primer is now ready forapplication to the substrate. Suitable substrates include metalsubstrates such as aluminum, aluminum alloys, cast aluminum, magnesium,magnesium alloys, titanium, zinc, galvanized zinc, zinc-coated steel,zinc alloys, zinc-iron alloys, zinc-aluminum alloys, steel, stainlesssteel, pickled steel, iron compounds, magnesium alloys, and the like.Preferred substrates for the practice of the present invention arealuminum and aluminum alloys. The substrate to be coated can be that ofa fabricated article, as described above, further including thecomponents and parts for these articles.

[0068] The coating mixtures of the invention can be applied to thesurfaces of a metal substrate using any conventional technique, such asspraying, painting with a brush, painting with rollers, dipping, and thelike, but they are most often applied by spraying. The usual spraytechniques and equipment for air spraying and electrostatic spraying andeither manual or automatic methods can be used. Preferred for thepractice of the present invention is spray coating.

[0069] It is preferred that the surface, such as a metal surface, beprepared to receive the coating. This preparation includes theconventional method of first cleaning the surface to remove grease andother contaminants. Once the surface is free of surface contaminants, itcan be treated to remove any oxide coating, and in certain instances toprovide a conversion coating to which the corrosion-inhibiting mixturecan more readily bond. In the event that the surface has a thick oxidecoating, then this coating can be removed by conventional means, such asimmersion in a series of sequential chemical baths containingconcentrated acids and alkalis that remove such a surface coating.

[0070] In most embodiments, the substrate or coated substrate isprepared prior to receiving the coating, i.e., is pretreated. Thispreparation includes the conventional method of first cleaning thesurface to remove grease and other contaminants. Once the surface isfree of surface contaminants, it can be treated to remove any oxidecoating by conventional means, such as by immersing the substrate in aseries of sequential chemical baths containing concentrated acids andalkalis known to remove such a surface coating. As noted above, in someembodiments, the substrate is treated to provide a conversion coating towhich the coating can more readily bond. Such a conversion coating canbe prepared by any means known in the art, such as by immersion inconcentrated chromic acid. When an aluminum substrate is used, forexample, this process produces a controlled mixture of aluminum oxideson the surface of an aluminum or aluminum alloy substrate.Alternatively, the surface can be treated with a boric acid/sulfuricacid or any other anodizing process. This process produces a controlledmixture of aluminum oxides in the surface of an aluminum or aluminumalloy substrate. Optionally, after the surface has been treated toprovide a conversion coating, the surface can be sealed by dipping thesubstrate into a dilute solution of chromic acid. The surface, whethersealed or unsealed, can then be coated with the coatings describedherein.

[0071] In one embodiment, the coating is applied to an aluminum anodizedsubstrate to create an aluminum anodized system with and without sealingin a chrome containing solution. In one embodiment, the coating isapplied to an aluminum anodized substrate to create an aluminum anodizedsystem with and without sealing in a rare earth solution. In oneembodiment, the coating is applied to a steel substrate with and withoutsealing in the appropriate solution.

[0072] The coatings described herein can be applied to a substrate usingany conventional technique, such as spraying, “painting” (e.g., with abrush, roller, and the like), dipping, and so forth. With regard toapplication via spraying, conventional (automatic or manual) spraytechniques and equipment used for air spraying and electrostaticspraying can be used. In other embodiments, the coating is anelectrolytic coating (e-coating) system, electrostatic (powder) coating,and the like. Various types of curing methods are described below.

[0073] The coatings described herein can be any suitable thickness,depending on the application requirements. In one embodiment, thecoating is between about 1 to about 3 mils thick. In another embodiment,the coating is between about 0.8 to about 1.2 mils thick.

[0074] Typically, after application of the coating, the coating is curedusing any suitable method. Typical curing methods include air drying,and/or heating and/or UV-curing methods. Other methods include, but arenot limited to, microwave cured systems, ultrasonic cured systems, andthe like. The method of curing will depend on the type of coatingmixture employed, the surface to which it is applied, and so forth.

[0075] Once the coating is applied and cured, it can either receivesubsequent topcoats, or be cured as a stand-alone coating. If thecoating is to receive a subsequent topcoat, or several subsequentcoatings, then the subsequent coating should be applied so as to becompatible with the coating layer already present, typically inaccordance with the resin and/or topcoat manufacturers' specifications.If the coating does not receive any subsequent topcoats, it can then beallowed to cure.

[0076] Additional Embodiments

[0077] In one embodiment, the coating composition is a self-primingtopcoat composition, or an enhanced self-priming topcoat composition.These coating compositions can be used on metals such as aluminum,aluminum alloys, cast aluminum, magnesium, magnesium alloys, titanium,zinc, zinc-coated steel, zinc alloys, zinc-iron alloys, zinc-aluminumalloys, bare and galvanized steel, stainless steel, pickled steel, ironcompounds, magnesium alloys, substrates having metal pretreatments, suchas chrome-based conversion coatings, anodized coatings, cobalt-basedconversion coatings, phosphate-based conversion coatings, silica-basedconversion coatings, rare earth-based conversion coatings, and stainlessmetal pretreatments for example, and polymers, polymer/metal composites,composites, coated substrates, and the like. In a preferred but notrequired embodiment, the self-priming topcoat composition, or theenhanced self-priming topcoat composition is applied over a conversioncoating that is less than three days old. Applying the self-primingtopcoat composition, or the enhanced self-priming topcoat compositionover a conversion coating has been found to maintain good adhesion ofthe coating to the substrate. It has also been found that conversioncoatings that are too thick for a given application can result incohesive failure in the conversion coating layer. As will be understoodby those of skill in the art with reference to this disclosure, theproper conversion coating performance and thickness, for a particularcoating composition, will be apparent and preferred coatings comply withMIL-C-5541.

[0078] In another embodiment, a process for preparing and using theself-priming topcoat composition, or the enhanced self-priming topcoatcomposition is provided. According to this embodiment, conventionalmethods for manufacturing a paint can be used. As will be understood bythose of skill in the art with reference to this disclosure, examples ofsuch methods include, but are not limited to, the use of drill pressespowered by compressed air or electricity, sand mills that useappropriate grinding media, and the like.

[0079] The invention will be further described by reference to thefollowing non-limiting examples, which are offered to further illustratevarious embodiments of the present invention. It should be understood,however, that many variations and modifications can be made whileremaining within the scope of the present invention.

EXAMPLE 1 Exemplary Mill Base Formulations

[0080] Group IIA pigments have been tested for corrosion resistance,including sulfates (e.g., anhydrous calcium sulfate, hydrated calciumsulfate, strontium sulfate, barium sulfate), metal phosphates (e.g.,hydrous calcium phosphate, anhydrous calcium phosphate and mono- anddi-hydrogen calcium phosphate, etc.), alone and in combination withother components. Two examples of the composition, concentrations,material ratios, vendor materials or vendor supplier, of apolyamide/epoxy water reducible primer mill base formulation containingthese types of compounds is shown below. Other formulations were alsotested:

[0081] Component: Polyamide Resin Blend  417 g Dispersing Agent   6 g2-Butanol Solvent  87 g Extender/Filler Pigment  490 g Mill Base Total:1000 g

[0082] Component: Polyamide Resin Blend  320 g Additive   5 g 2-ButanolSolvent  67 g TiO₂(R-960)  134 g Co-Inhibitor(s)  100 g Extender/FillerPigment  374 g Mill Base Total: 1000 g

[0083] The concentration of the corrosion inhibitors used as individualsrange from about 0.1 wt % to about 90 wt %.

[0084] Additional Information and Procedures Used

[0085] The wt % of inhibitor is based on a fully catalyzed and waterreduced primer and the spray viscosity is equal to about 22 seconds on astandard EZ Zhan 2 Cup.

[0086] The polyamide/epoxy water reducible primer mill base was thenwell mixed with appropriate amounts of the epoxy catalyst blend asdescribed above and recommended by the supplier of the resin. Oneexample of an epoxy catalyst/activator would consist of a solvent, anadditive, and a resin blend, such as Deft's epoxy/nitroethane solution,manufacturer's code number 44WO16CAT.

[0087] Once the appropriate amounts of epoxy catalyst and mill base werewell mixed together, the appropriate amount of water was then slowlymixed into the primer mill base/epoxy catalyst blend. The purity andamount of the water added depends on what is recommended by the supplierof the coating system based as described above. Procedures for mixing ofthe primer, shelf life of primer mill base, spray life of catalyzed andwater reduced primer, and the like, are in accordance with thespecifications of the supplier of the resin material.

[0088] Examples of such primer formulations that have been prepared andevaluated are provided in Table 3 below.

EXAMPLE 2 Primer Mill Base Formulation

[0089] Oxides, either anhydrous or hydrated, and hydroxides of rareearth elements have been evaluated as being non-toxic alternatives tochromates. Rare earth oxides, either anhydrous or hydrated, andhydroxides, such as Cerium (IV) Oxide, Cerium (IV) Oxide dihydrate,Praseodymium (III) Oxide, and the like, have been incorporated intopolyamide/epoxy water reducible primer formulations. One example of apolyamide/epoxy water reducible primer mill base formulation containingrare earth salts is as follows: Polyamide Resin Blend  341 g Additive  5 g 2-Butanol Solvent  71 g TiO₂(R-960)  143 g Rare Earth Oxide(s)  40g Extender/Filler Pigment  400 g Mill Base Total: 1000 g

[0090] The concentration of the corrosion inhibitors used as individualsrange from about 0.4 wt % (Pr₂O₃ panel A151) to about 12 wt %(CeO₂.xH₂O). Additional procedures used in this Example were asdescribed in Example 1 under “Additional Information and ProceduresUsed.” See Table 3 in Example 12 for test results.

EXAMPLE 3

[0091] Mixed oxides, either anhydrous or hydrated, and hydroxides ofmixed oxides of rare earth elements have been evaluated as beingnon-toxic alternatives to chromates. Rare earth mixed oxides, eitheranhydrous or hydrated, and hydroxides, such as Terbium (III/IV) Oxide,Praseodymium (III/IV) Oxide, and the like, have been incorporated,individually and in combination, into polyamide/epoxy water reducibleprimer formulations. One example of a polyamide/epoxy water reducibleprimer mill base formulation containing rare earth salts is as follows:

Primer Mill Base Formulation

[0092] Polyamide Resin Blend  328 g Dispersing Agent   5 g 2-ButanolSolvent  68 g TiO₂  137 g Rare Earth Mixed Oxide(s)  77 g(Anhy./Hydrous./Hydroxide) Extender/Filler Pigment  385 a Mill BaseTotal: 1000 g

[0093] The concentration of the corrosion inhibitors used as individualsrange from about 1 wt % (Pr₆O₁, panel A22) to about 22.2 wt % (Pr₆O₁₁panel 227). Additional procedures used in this Example were as describedin Example 1 under “Additional Information and Procedures Used.” SeeTable 3 in Example 12 for test results.

EXAMPLE 4

[0094] Amine-based aliphatic, aromatic, cyclic, and or sulfur containingcompounds have been evaluated as being non-toxic alternatives tochromates. Amine-based aliphatic, aromatic, cyclic, and or sulfurcontaining compounds, for example amino acids, such as L-arginine,D,L-arginine, D-methionine, L-methionine, D,L-methionine, glycine,proline, L-cysteine, etc., and other amine-based compounds, such asethylenediaminetetra-acetic acid (EDTA), di-sodium salts of EDTA, andthe like, have been incorporated into polyamide/epoxy water reducibleprimer formulations. One example of a polyamide/epoxy water reducibleprimer mill base formulation containing these types of compounds is asfollows:

Primer Mill Base Formulation

[0095] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Amine-based aliphatic, aromatic, cyclic,  14 gand/or sulfur containing compound(s) Extender/Filler Pigment  411 g MillBase Total: 1000 g

[0096] The concentration of the amino acids used range from about 0.5 wt% (D,L-Methionine panel 0214) to about 1.5 wt % (D,L-Methionine panel232). Additional procedures used in this Example were as described inExample 1 under “Additional Information and Procedures Used.” See Table3 in Example 12 for test results.

EXAMPLE 5

[0097] Derivatives of amine-based aliphatic, aromatic, cyclic, and orsulfur containing compounds have been evaluated and verified as beingnon-toxic alternatives to chromates. Derivatives of amine-basedaliphatic, aromatic, cyclic, and or sulfur containing compounds, such asD,L-methionine sulfoxide, L-methionine methylsulfonium iodide, and thelike, have been incorporated into polyamide/epoxy water reducible primerformulations. One example of this composition, concentrations, materialratios, vendor materials, or vendor supplier, of a polyamide/epoxy waterreducible primer mill base formulation containing these types ofcompounds is as follows:

Primer Mill Base Formulation

[0098] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Derivative(s) of amine-based aliphatic,  14 garomatic, cyclic, and/or sulfur and/or iodide containing compound(s)Extender/Filler Pigment  411 g Mill Base Total: 1000 g

[0099] The concentration of the corrosion inhibitors used as individualsrange from about 0.5 wt % (D,L-methionine sulfoxide panel 0179) to about1.1 wt % (D,L-Methionine Sulfoxide panel 234). Additional proceduresused in this Example were as described in Example 1 under “AdditionalInformation and Procedures Used.” See Table 3 in Example 12 for testresults.

EXAMPLE 6

[0100] Gelatin and gelatin derivatives have been evaluated as beingnon-toxic alternatives to chromates. Gelatin and gelatin derivatives,such as but not limited to animal gelatins and derivatives, fishgelatins and derivatives, and the like, have been incorporated intopolyamide/epoxy water reducible primer formulations. One example of acomposition, concentrations, material ratios, vender materials, orvender supplier, of a polyamide/epoxy water reducible primer mill baseformulation containing these types of compounds is as follows:

Primer Mill Base Formulation

[0101] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Gelatin(s) and or  14 g GelatinDerivative(s)Extender/Filler Pigment  411 g Mill Base Total: 1000 g

[0102] The concentration of the corrosion inhibitors used as individualsrange from about 0.03 wt % (Animal Gelatin+Pr₆O₁₁+Ce(NO₃)₃ panel A66E)to about 1 wt % (Animal Gelatin+Pr₆O₁₁+Ce(NO₃)₃ panel A28). Additionalprocedures used in this Example were as described in Example 1 under“Additional Information and Procedures Used.” See Table 3 in Example 12for test results.

EXAMPLE 7

[0103] Chirally Active Dextrins have been evaluated as being non-toxicalternatives to chromates. Chirally Active Dextrins, such as alphacyclodextrin, beta cyclodextrin, sulfonated cyclodextrins, and the like,have been incorporated into polyamide/epoxy water reducible primerformulations. One example of a polyamide/epoxy water reducible primermill base formulation containing these types of compounds is as follows:

Primer Mill Base Formulation

[0104] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Chirally Active Dextrin(s)  14 gExtender/Filler Pigment  411 g Mill Base Total: 1000 g

[0105] The concentration of the corrosion inhibitors used was primarilyat about 1.5 wt %(Cyclodextrin+Ce(NO₃)₃+Pr₆O₁₁ panel C41. Additionalprocedures used in this Example were as described in Example 1 under“Additional Information and Procedures Used.” See Table 3 in Example 12for test results.

EXAMPLE 8

[0106] Organic-based ionic exchange resins have been evaluated as beingnon-toxic alternatives to chromates. Organic-based ionic exchangeresins; such as organic-based cationic resins, for example Whatmanfibrous cellulose phosphate cation exchanger P11, Whatman fibrouscarboxymethyl cellulose cation exchanger CM23, and the like, and anionicexchange resins, for example Whatman fibrous diethylaminoethyl celluloseanion exchanger DE23, and Reilex 402 Polymer, and the like, have beenincorporated into polyamide/epoxy water reducible primer formulations.One example of a polyamide/epoxy water reducible primer mill baseformulation containing rare earth salts is as follows:

Primer Mill Base Formulation

[0107] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂ (R-960)  146 g Organic-Based Ionic Exchange Resin(s) 14 g Extender/Filler Pigment  411 g Mill Base Total: 1000 g

[0108] The concentration of the corrosion inhibitors used as individualsrange from about 0.5 wt % (CM23+Pr₆O₁₁ panel 1216) to about 1 wt % (DE23, panel 110). Additional procedures used in this Example were asdescribed in Example 1 under “Additional Information and ProceduresUsed.” See Table 3 in Example 12 for test results.

EXAMPLE 9

[0109] Organic-based, pre-exchanged ionic exchange resins have beenevaluated as being non-toxic alternatives to chromates. Organic-basedcationic and or anionic ionic exchange resins that have beenpre-exchanged with rare earth cations and or amino acids; for exampleWhatman fibrous cellulose phosphate cation exchanger P11 pre-exchangedwith a solution containing salts, oxides and mixed oxides, and orcompounds or rare earths, Whatman fibrous cellulose phosphate cationexchanger P11 pre-exchanged with a solution containing amine-basedaliphatic, aromatic, cyclic, and or sulfur and or iodide containingcompounds and or derivatives of any of the above, etc. have beenincorporated into polyamide/epoxy water reducible primer formulations.One example of a polyamide/epoxy water reducible primer mill baseformulation containing these types of compounds is as follows:

Primer Mill Base Formulation

[0110] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Pre-Exchanged Organic-Based  14 g IonicExchange Resin(s) Extender/Filler Pigment  411 g Mill Base Total: 1000 g

[0111] The concentration of the corrosion inhibitors used range fromabout 0.5 wt % (P11+Pr(NO₃)₃, panel 1162) to about 2.5 wt %(P11+D,L-Methionine panel 15). Additional procedures used in thisExample were as described in Example 1 under “Additional Information andProcedures Used.” See Table 3 in Example 12 for test results.

EXAMPLE 10

[0112] Metal sulfates have been evaluated as being nontoxic alternativesto chromates. Metal sulfates, such as praseodymium sulfate or other rareearth sulfates, magnesium sulfate, calcium sulfate, strontium sulfate,and the like, have been incorporated into polyamide/epoxy waterreducible primer formulations. One example of the composition,concentrations, material ratios, vendor materials, or vendor supplier,of a polyamide/epoxy water reducible primer mill base formulationcontaining these types of compounds is as follows:

Primer Mill Base Formulation

[0113] Polyamide Resin Blend  351 g Dispersing Agent   5 g 2-ButanolSolvent  73 g TiO₂  146 g Metal Sulfate(s)  14 g Extender/Filler Pigment 411 g Mill Base Total: 1000 g

[0114] The concentration of the corrosion inhibitors used as individualsrange from about 1.4 wt % (Pr₂(SO₄)₃ panel A220) to about 18.5 wt %(SrSO₄, panel 267). Additional procedures used in this Example were asdescribed in Example 1 under “Additional Information and ProceduresUsed.” See Table 3 in Example 12 for test results.

EXAMPLE 11

[0115] Combinations of all of the above have been evaluated as beingnon-toxic alternatives to chromates. Combinations of all of the above,such as L-arginine+praseodymium(III/IV)oxide+calcium sulfate dihydrate,praseodymium sulfate+calcium sulfate+arginine, praseodymium(III/IV)oxide+calcium sulfate+methionine, praseodymium(III)oxide+praseodymiumpre-exchanged cationic exchange resin P11+praseodymium(III/IV)oxide,etc., have been incorporated into polyamide/epoxy water reducible primerformulations. One example of a polyamide/epoxy water reducible primermill base formulation containing rare earth salts is as follows:

Primer Mill Base Formulation

[0116] Polyamide Resin Blend  336 g Dispersing Agent   5 g 2-ButanolSolvent  71 g TiO₂  140 g Pre-Exchanged Organic-Base  14 g IonicExchange Resin Pr₆O₁₁  40 g Extender/Filler Pigment  394 g Mill BaseTotal: 1000 g

[0117] The concentration of the corrosion inhibitors used ascombinations range from about 0.1 wt % (Ce(NO₃)₃+Free EDTA, panel D36)to about 30.6 wt % (Ce(NO₃)₃+Na₂EDTA+Pr₆O₁₁+CaSO₄.2H₂O panel A38).Additional procedures used in this Example were as described in Example1 under “Additional Information and Procedures Used.” See Table 3 inExample 12 for test results.

EXAMPLE 12

[0118] Test Results on Exemplary Coatings

[0119] Many of the formulations noted in the previous examples weretested on various substrates for corrosion resistance. The CorrosionRating Scale used is shown in Table 2. Examples of primer formulationsthat were prepared and evaluated are provided in Table 3.

[0120] Starting Materials

[0121] The Deft SrCr Primer (44GN072) was obtained from Deft Inc. havingoffices in Irvine, Calif. As noted above, the Raven materials, as wellas the Ultra II materials, were obtained from Columbian ChemicalsCompany having offices in Marietta, Ga. The LHD, U47 and PLD materialswere obtained from Sun Chemical having offices in Cincinnati, Ohio.Pr₆O₁₁ was obtained from Alfa Aesar Co. having offices in Ward Hill,Mass. Conductive carbon, non-conductive carbon, and activated carbonwere obtained from Alpha Aesar having offices in Ward Hill, Mass.CaSO₄2H₂O was obtained from US Gypsum from Chicago, Ill. SrSO₄ wasobtained from Excalibar of Huston, Tex.

[0122] Test Procedure

[0123] The coating was sprayed onto different metal substrates andallowed to dry (cure) naturally over time. Typically this took about oneweek. Edges and backs of samples were taped and front surfaces werescribed with an “X” pattern according to ASTM B117 procedure. Tests wererun according to ASTM B117 procedure for either 500 or 3000 hours andthe results evaluated according to the Keller Corrosion Rating Scaleshown in Table 2.

Primer Panel Summary

[0124] TABLE 2 Corrosion Codes/Rankings Employed in Table 3 Code Scribeline ratings description 1. Scribe line beginning to darken or shinyscribe 2. Scribe lines >50% darkened 3. Scribe line dark 4. Severallocalized sites of white salt in scribe lines 5. Many localized sites ofwhite salt in scribe lines 6. White salt filling scribe lines 7. Darkcorrosion sites in scribe lines 8. Few blisters under primer alongscribe line (<12) 9. Many blisters under primer along scribe line 10. Slight lift along scribe lines. 11.  Coating curling up along scribe.12.  Pin point sites/pits of corrosion on organic coating surface({fraction (1/16)} to ⅛ in diameter - about 0.16 cm (0.06 in) to about0.32 cm (0.13 in) 13.  One or more blisters on surface away from scribe14.  Many blisters under primer away from scribe 15.  Starting toblister over surface Scribe Line Activity (corrosion creepage beyondscribe) A. No creepage B. 0 to {fraction (1/64)} in - about 0 cm (in) toabout 0.04 cm (0.02 in) C. {fraction (1/64)} to {fraction (1/32)} in -about 0.04 cm (0.02 in) to about 0.08 cm (0.03 in) D. {fraction (1/32)}to {fraction (1/16)} in - about 0.08 cm (0.03 in) to about 0.16 cm (0.06in) E. {fraction (1/16)} to ⅛ in - about 0.16 cm (0.06 in) to about 0.32cm (0.13 in) F. {fraction (3/16)} to ¼ in - about 0.2 cm (0.48 in) toabout 0.5 cm (0.25 in) G. ¼ to ⅜ in - about 0.6 cm (0.25 in) to about0.95 cm (0.38 in)

[0125] TABLE 3 Panels Prepared and Evaluated Weight Percent* 2000 HRSPanel Corrosion Inhibitor Extender/ Salt Fog Number Inhibitor Conc.Transport Enhancer Rating 10 SrCrO₄ — — 1 A D1 Ce(NO₃)₃  0.15 Kaolin 3,6A D12 Ce(NO₃)₃ 5   Kaolin 3,6 A D3 Ce(NO₃)₃ 3   CaSO₄ (anhy.) 3,6 A D40Ce(NO₃)₃ 0.4 CaSO₄ (anhy.) 3,6 A D13 Ce(NO₃)₃ 5   CaSO₄ (anhy.) 3,6 AD42 Ce(NO₃)₃ 0.4 CaSO₄.2H₂O 3,5 A D140 Ce(NO₃)₃  .05 CaSO₄.2H₂O 3,5 AD49 Ce(NO₃)₃ 5   CaSO₄.2H₂O 3,6 A D73 Ce(NO₃)₃ .75/0.5 CaSO₄.2H₂O 3,6 AH₃(CF₃SO₃)₃ D44 Ce(NO₃)₃ 0.5 Deft (Mistron 600) 3,6 A D14Ce(NO₃)₃/BaB₂O₄ 8/8 Kaolin 3,6 A Gen I CeO₂.2H₂O 32   Mistron 600 3,6 AD11 Ce(NO₃)₃/CePO₄ 0.3/0.3 Kaolin 3,6 A D15 Ce(NO₃)₃/Pr(NO₃)₃/ 1/1/1Kaolin 3,5 A BaB₂O₄ D16 Ce(NO₃)₃/Pr(NO₃)₃/ 0.4 CaSO₄.2H₂O 3,5 A BaB₂O₄D17 Ce(NO₃)₃/Pr(NO₃)₃/ 0.4/0.4/ Nicron 604 3,6 A BaB₂O₄ 0.4 D18 — 0.0CaSO₄.2H₂O 3,5 A D19 — 0.0 Nicron 604 3,6 A C1 Na₂EDTA 0.9 CaSO₄.2H₂O3,5 A D50 Ce(NO₃)₃ + Acid 1.5 CaSO₄.2H₂O 3,4 A D51 Ce(NO₃)₃ + Base 1.5CaSO₄.2H₂O 3,4 A D53 Ce(NO₃)₃ + Base 1.5 CaSO₄.2H₂O 3,4 A D54 Ce(NO₃)₃ +Acid + H₂O₂ 1.5 CaSO₄.2H₂O 3,4 A D55 Ce(NO₃)₃ + Base + H₂O₂ 1.5CaSO₄.2H₂O 3,4 A D56 Ce(NO₃)₃ + Base + H₂O₂ 1.5 CaSO₄.2H₂O 3,4 A A1PrCl₃ 3   Kaolin 3,6 A A2 Pr(NO₃)₃ 3   Kaolin 3,6 A A5 Pr(NO₃)₃ 1  Kaolin 3,6 A A4 Pr(NO₃)₃ 8   Kaolin 3,6 A A11 Pr(NO₃)₃/BaB₂O₄ 3/3 Kaolin3,6 A A3 Pr(NO₃)₃ 3   CaSO₄ (anhy.) 3,5 A A8 Pr(NO₃)₃ 1   CaSO₄ (anhy.)3,5 A A9 Pr(NO₃)₃ 5   CaSO₄ (anhy.) 3,5 A A12 Pr(NO₃)₃ 0.5 CaSO₄.2H₂O3,5 A A26 Pr(NO₃)₃/Pr₆O₁₁ 1.5/1.5 CaSO₄.2H₂O 3,4 A A33 Pr(NO₃)₃/Pr₆O₁₁2/3.1 CaSO₄.2H₂O 3,4 A A46 Pr(NO₃)₃/Ce(NO₃)₃ 0.7/1 CaSO₄.2H₂O 3,4 A A19PrCO₃ 1   CaSO₄.2H₂O 3,5 A A21 PrCO₃ 3   Nicron 604 3,6 A A63 Pr(NO₃)₃ +Acid 1.5 CaSO₄.2H₂O 3,5 A A64 Pr(NO₃)₃ + Base 1.5 CaSO₄.2H₂O 3,4 A A65Pr(NO₃)₃ + Base 1.5 CaSO₄.2H₂O 3,4 A A28 Ce(NO₃)₃/Pr₆O₁₁/ 3.1/1/1CaSO₄.2H₂O 3,4 A Gelatin A66E Ce(NO₃)₃/Pr₆O₁₁/ 1.5/1.5/ CaSO₄.2H₂O 1,4 AGelatin 0.03 A31 Ce(NO₃)₃/Pr(NO₃)₃/ 1/0.7/ CaSO₄.2H₂O 2,4 A Gelatin 0.2D28 Ce(NO₃)₃/Gelatin 3/0.2 CaSO₄.2H₂O 2,4 A A38 Ce(NO₃)₃/Na₂EDTA/ 1/16/CaSO₄.2H₂O 2,4 A Pr₆O₁₁ 3.1 C13 Ce(NO₃)₃/Na₂EDTA/ 0.5/16/1 CaSO₄.2H₂O2,4 A Pr₆O₁₁ C14 Ce(NO₃)₃/Na₂EDTA/ 0.5/16/ CaSO₄.2H₂O 2,4 A Pr₆O₁₁/AlPO₄1/3 A37 Ce(NO₃)₃/Pr₆O₁₁ 1/3.1 CaSO₄.2H₂O 2,4 A A47 Ce(NO₃)₃/Pr₆O₁₁1.4/0.7 CaSO₄.2H₂O 2,4 A C18 Ce(NO₃)₃/Na₂EDTA/ 0.5/16/1 CaSO₄ (anhy.)3,4 A Pr₆O₁₁ C19 Ce(NO₃)₃/Na₂EDTA/ 0.5/16/ CaSO₄ (anhy.) 3,4 APr₆O₁₁/AlPO₄ 1/3 A48 Ce(NO₃)₃/Pr₆O₁₁ 1.4/0.7 CaSO₄ (anhy.) 3,4 A NH1Nd(NO₃)₃ 3   Kaolin 3,6 A NH2 Sm(C₂H₃O₂)₃ 3   Kaolin 3,6 A K1 K-White1   CaSO₄.2H₂O 3,6 A (Commercial) K2 K-White 3   CaSO₄.2H₂O 2,4 A(Commercial) C1 Na₂EDTA 0.9 CaSO₄.2H₂O 3,6 A C2 Na₂EDTA 1.8 CaSO₄.2H₂O3,6 A D26 Ce(NO₃)₃/Na₂EDTA 0.25/0.25 CaSO₄.2H₂O 3,6 A D1:.5Ce(NO₃)₃/Na₂EDTA 4.7/4.7 CaSO₄.2H₂O 3,6 A C3 Free EDTA SaturatedCaSO₄.2H₂O 3,6 A D36 Ce(NO₃)₃/Free 0.06/0.06 CaSO₄.2H₂O 3,6 A EDTA D32Ce(NO₃)₃/Free 1.4/0.6 CaSO₄.2H₂O 3,6 A EDTA D38 Ce(NO₃)₃/Na₂EDTA/ 0.7/2/CaSO₄.2H₂O 3,6 A Gelatin 0.2 C5 Pr₆O₁₁/Na₂EDTA 3.1/16 CaSO₄.2H₂O 2,4 AC5 Pr₆O₁₁/Na₂EDTA 1.5/16 CaSO₄.2H₂O 2,4 A A51 Pr(CF₃SO₃)₃ 1.5 DeftPrimer 2,4 A (Mistron 600) A68 Pr(CF₃SO₃)₃ 2.2 Deft Primer 2,5 A(Mistron 600) A54 Pr(CF₃SO₃)₃ 1.5 CaSO₄.2H₂O 2,4 A A59 Pr(CF₃SO₃)₃ 1  CaSO₄.2H₂O 2,4 A A67 Pr(CF₃SO₃)₃ 2.2 CaSO₄.2H₂O 2,4 A D71 Pr(NO₃)₃/1.5/2.2 CaSO₄.2H₂O 3,4 A Pr(CF₃SO₃)₃ NH10 Li₂SO₄ 2.5 CaSO₄.2H₂O 3,4 ANH11 Li₂SO₄ 2.5 Deft Primer 3,6 A (Mistron 600) A10 Pr₆O₁₁ 3   CaSO₄(anhy.) 3,5 A A40 Pr₆O₁₁ 5   CaSO₄ (anhy.) 3,5 A A22 Pr₆O₁₁ 1  CaSO₄.2H₂O 3,4 A A23 Pr₆O₁₁ 5   CaSO₄.2H₂O 3,4 A A41 Pr₆O₁₁ 3  CaSO₄.2H₂O 2,5 A A25 Pr₆O₁₁ 3   Nicron 604 3,6 A A50 Pr₆O₁₁ 1.5 DeftPrimer 3,6 A (Mistron 600) 8-X6 Pr₆O₁₁ 1.5 Deft Primer 3,6 A (Mistron600) A70 Pr₆O₁₁ 5   Deft Primer 2,4 A (Mistron 600) 8-X7 Pr₆O₁₁ 1.5CaSO₄.2H₂O 3,6 A A-69 Pr₆O₁₁ 5   CaSO₄.2H₂O 1,4 A C4 D,L-Methionine 0.5CaSO₄.2H₂O 3,6 A C31 D,L-Methionine 0.5 CaSO₄.2H₂O 2,4 A C9D,L-Methionine 0.5 CaSO₄ (anhy.) 3,6 A C11 D,L-Methionine/ 0.5/2CaSO₄.2H₂O 3,6 A Ce(NO₃)₃ C16 D,L-Methionine/ 0.5/ CaSO₄.2H₂O 3,6 ACe(NO₃)₃ 1.5 C17 D,L-Methionine/ 0.5/3 CaSO₄.2H₂O 3,6 A Ce(NO₃)₃ D60D,L-Methionine/ 0.5/3 Deft Primer 3,6 A Ce(NO₃)₃ (Mistron 600) C10D,L-Methionine/ 0.5/2 CaSO₄ (anhy.) 3,6 A Ce(NO₃)₃ C21 D,L-Methionine/0.5/ CaSO₄ (anhy.) 3,6 A Ce(NO₃)₃ 1.5 C22 D,L-Methionine/ 0.5/3 CaSO₄(anhy.) 3,6 A Ce(NO₃)₃ C6 D,L-Methionine/ 3.1/ CaSO₄.2H₂O 2,4 A Pr₆O₁₁3.1 C15 D,L-Methionine/ 0.5/1 CaSO₄.2H₂O 2,5 A Pr₆O₁₁ C8 D,L-Methionine/0.5/ CaSO₄.2H₂O 3,4 A Pr₆O₁₁ 3.1 C35 D,L-Methionine/ 0.5/ CaSO₄.2H₂O 2,4A Pr₆O₁₁/ 1.5/1.5 Ce(NO₃)₃ C37 L-Arginine/Ce(NO₃)₃ 1.5/1.5 CaSO₄.2H₂O2,5 A D57 L-Arginine/Ce(NO₃)₃ 2/1 CaSO₄.2H₂O 2,5 A D58L-Arginine/Ce(NO₃)₃ 2/1 Deft Primer 3,6 A (Mistron 600) C40L-Arginine/Ce(NO₃)₃/ 1.5/1.5/ CaSO₄.2H₂O 2,4 A Pr₆O₁₁ 1.5 C38Cyclodextrin/Ce(NO₃)₃ 1.5/1.5 CaSO₄.2H₂O 2,5 A C41Cyclodextrin/Ce(NO₃)₃/ 1.5/1.5/ CaSO₄.2H₂O 2,5 A Pr₆O₁₁ 1.5 C39Cyclodextrin/Ce(NO₃)₃/ 1.5/1.5/ CaSO₄.2H₂O 2,5 A EDTA 1.5 C42Cyclodextrin/Ce(NO₃)₃/ 1.5/1.5 CaSO₄.2H₂O 2,5 A Pr₆O₁₁/EDTA 1.5/1.5 0179D,L-Methionine 0.5 CaSO₄.2H₂O 1 A Sulfoxide 0160 L-Methionine 0.5CaSO₄.2H₂O 1 A Methylsulfonium Iodide I162 P11 + Pr(NO₃)₃ 0.5 CaSO₄.2H₂O2 A I163 CM23 + Pr(NO₃)₃ 0.5 CaSO₄.2H₂O 2 A C70 Reilex 1   CaSO₄.2H₂O3,6 A C72 Pr₆O₁₁/Reilex 1.5/1 CaSO₄.2H₂O 2,5 A I2 Methionine/ 1.5/1CaSO₄.2H₂O 2,5 A Reilex I3 P11 1   CaSO₄.2H₂O 2,3 A I4 Pr₆O₁₁/P11 1.5/1CaSO₄.2H₂O 1,4 A I5 Methionine/P11 1.5/1 CaSO₄.2H₂O 3,6 A I6 CM23 1  CaSO₄.2H₂O 2,4 A I7 PrFMS/CM23 1.5/1 CaSO₄.2H₂O 2,3 A I8 Pr₆O₁₁ CM231.5/1 CaSO₄.2H₂O 1 A I9 Methionine/ 1.5/1 CaSO₄.2H₂O 2,3 A CM23 I10 DE231   CaSO₄.2H₂O 2 A Generation Vb A136 Pr₂O₃ 1.5 10.5% CaSO₄.2H₂O 1 AA137 Pr₆O₁₁-m 1.5 10.5% CaSO₄.2H₂O 1 A A138 PrO₂ 1.5 10.5% CaSO₄.2H₂O 1A A139 Pr₆O₁₁ 1.5 10.5% CaSO₄.2H₂O 1 A D140 Ce(NO₃)₃  .05 10.5%CaSO₄.2H₂O 3,5 A A141 Pr₂O₃ 1.5 12.4% CaSO₄.2H₂O 1 A A142 Pr₆O₁₁-m 1.512.4% CaSO₄.2H₂O 1 A A143 PrO₂ 1.5 12.4% CaSO₄.2H₂O 1 A A144 Pr₆O₁₁ 1.512.4% CaSO₄.2H₂O 1 A D145 Ce(NO₃)₃  .05 12.4% CaSO₄.2H₂O 3,5 A A146Pr₂O₃ 1.5 15.6% CaSO₄.2H₂O 1 A A147 Pr₆O₁₁-m 1.5 15.6% CaSO₄.2H₂O 1 AA148 PrO₂ 1.5 15.6% CaSO₄.2H₂O 1 A A149 Pr₆O₁₁ 1.5 15.6% CaSO₄.2H₂O 1 AA150 Pr₂O₃ 1.5 10.1% CaSO₄.2H₂O 1 A A151 Pr₂O₃ 0.4 10.1% CaSO₄.2H₂O 1 AA152 Pr₂O₃ 0.4 14.6% CaSO₄.2H₂O 1 A A153 Pr₂O₃ 3.7 13.4% CaSO₄.2H₂O 1 AGeneration Vd A220 Pr₂(SO₄)₃ 1.4 15% CaSO₄.2H₂O 1 A T221 Tb₃O₇ 1.4 15%CaSO₄.2H₂O 1 A 223 Pr(OH)₃ 1.4 15% CaSO₄.2H₂O 1,4 A 224 Pr₆O₁₁  1.9514.8% CaSO₄.2H₂O 1 A 225 Pr₆O₁₁ 5.6 14.2% CaSO₄.2H₂O 1 A 226 Pr₂O₃ 1.515% CaSO₄.2H₂O 1 A 227 Pr₆O₁₁ 22.4  0% CaSO₄.2H₂O 2,5 A 228Pr₂O₃/Pr₆O₁₁/ 1.4/1.4 14% CaSO₄.2H₂O 1 A PrSO₄/D,L 0.8/.25 Methionine229 PrO₂/ 0.4/1.1 15% CaSO₄.2H₂O 1 A Glycine 230 D- 1.1 15.2% CaSO₄.2H₂O1 A Methionine 231 D,L- 0.5 15.4% CaSO₄.2H₂O 1 A Methionine 232 D,L- 1.515% CaSO₄.2H₂O 1 A Methionine 233 L-Cystiene 1.1 15.2% CaSO₄.2H₂O 1 A234 D,L- 1.1 15.2% CaSO₄.2H₂O 1 A Methionine Sulfoxide 235 L-Arginine1.1 15.2% CaSO₄.2H₂O 1 A 237 Pr₆O₁₁ 1.5 15% CaSO₄.2H₂O 1 A 238 Pr₂O₃ 1.515% CaSO₄.2H₂O 1 A 239 Pr₆O₁₁ 1.5 19.5% BaSO₄ 3,5 A 240 Pr₂O₃ 1.5 19.5%BaSO₄ 3,5 A 241 Pr₆O₁₁ 1.5 17.3% SrSO₄ 1 A 242 Pr₂O₃ 1.5 17.3% SrSO₄ 1 A243 Pr₆O₁₁ 1.5 15% MgSO₄ Not Tested 244 Pr₂O₃ 1.5 15% MgSO₄ Not TestedGeneration IV D80 Basic Extender 45   Deft (Mistron 600) 3,5 A D84CaSO₄.2H₂O 45   10.6% CaSO₄.2H₂O 1,4 A 1 CaSO₄.2H₂O 100    10.6%CaSO₄.2H₂O 1,4 A 54 SrSO₄ 100    SrSO₄ 1 A RA CaSO₄.2H₂O 77   10.6%CaSO₄.2H₂O 1,5 A 420A RA SrSO₄.2H₂O 85   SrSO₄.2H₂O 1,5 A 420E A81Pr(CF₃SO₃)₃ 1.5 Deft (Mistron 600) 3,4 A A82 Pr₆O₁₁ 1.5 Deft (Mistron600) 3,4 A A83 Pr(CF₃SO₃)₃ 0.7 Deft (Mistron 600) 3,4 A A85 Pr(CF₃SO₃)₃1.5 10.6% CaSO₄.2H₂O 2 A A86 Pr₆O₁₁ 1.5 10.6% CaSO₄.2H₂O 1,4 A A87Pr₆O₁₁ 3   10.6% CaSO₄.2H₂O 1 A C88 Pr₆O₁₁/ 1.5/ 10.6% CaSO₄.2H₂O 1 AD,L-Methionine/ 0.5/ L-Arginine 0.5 C89 D,L-Methionine/ 0.5/ 10.6%CaSO₄.2H₂O 1 A L-Arginine 0.5 D90 Ce(NO₃)₃ 0.5 10.6% CaSO₄.2H₂O 1 A C91Ce(NO₃)₃/ 0.5/ 10.6% CaSO₄.2H₂O 2 A L-Arginine 0.5 A92 Ce(NO₃)₃/Pr₆O₁₁0.51/1 10.6% CaSO₄.2H₂O 2,4 A A93 Pr(CF₃SO₃)₃ 3   12.3% CaSO₄.2H₂O 2 AA94 Pr₆O₁₁ 1.5 12.3% CaSO₄.2H₂O 1 A A95 Pr₆O₁₁ 3   12.3% CaSO₄.2H₂O 1,4A C96 D,L-Methionine/ 0.5/ 12.3% CaSO₄.2H₂O 1 A L-Arginine 0.5 C97Ce(NO₃)₃/ .05/ 12.3% CaSO₄.2H₂O 2 A L-Arginine 0.5 A98 Pr₆O₁₁ 3   12.3%CaSO₄.2H₂O 1 A Generation Vc 199 — 0   15.6% CaSO₄.2H₂O 2 A A200 Pr₂O₃1.4 15% CaSO₄.2H₂O 1 A A201 Pr₂O₃ 2.8 14.5% CaSO₄.2H₂O 1 A A202 Pr₂O₃3.7 14.1% CaSO₄.2H₂O 1 A A201 Pr₂O₃ hand 1.5 15% CaSO₄.2H₂O 1 A mixedA204 PrO₂ 1.4 15% CaSO₄.2H₂O 1 A A205 PrO₂ 2.2 14.7% CaSO₄.2H₂O 2 A A206PrO₂ - hand 1.5 15% CaSO₄ .2H₂O 1 A mixed A207 PrO₂ + Pr₂O₃ 1.4 15%CaSO₄.2H₂O 1 A A208 PrO₂ + Pr₂O₃ 2.2 14.7% CaSO₄.2H₂O 1 A A209 PrO₂ +Pr₂O₃ 1.5 15% CaSO₄.2H₂O 1 A hand mixed A210 Pr₆O₁₁ 1.4 15% CaSO₄.2H₂O 1A A211 Pr₆O₁₁ 2.8 14.5% CaSO₄.2H₂O 1 A A212 Pr₆O₁₁ 3.7 14.1% CaSO₄.2H₂O1 A A213 Pr₆O₁₁ - hand 1.5 15% CaSO₄.2H₂O 1 A mixed O214 D,L-Methionine0.5 15.4% CaSO₄.2H₂O 1 A O215 D,L-Methionine/ 0.5/ 14.8% CaSO₄.2H₂O 1 APr₆O₁₁ 1.4 I216 CM23/Pr₆O₁₁ 0.5/2.6 14.3% CaSO₄.2H₂O 2 A A219 Pr₆O₁₁ 1.415% CaSO₄.2H₂O 1 A

EXAMPLE 13 Enhanced Self-Priming Topcoat Base Formulation

[0126] Enhanced self-priming topcoat base formulations comprising one ormore Group I A or Group II A, and/or yttrium, and/or lanthanidecompounds, such as metal sulfates, metal phosphates, metal nitrates,and/or metal silicates and the like; and optionally one or moreco-inhibitors such as, rare earth compounds, metal oxides, borates,metaborates, silicates, phosphates, phosphonates, aniline, polyaniline,and the like, were prepared. An exemplary formulation is shown below inTable 4. TABLE 4 Enhanced Self-Priming Topcoat Base FormulationComponent Mass (g) Polyester Resin Blend (binder) 130 Fluorinated ResinBlend (binder) 240 Dispersing Agent 6 Ketone Solvent 77 VOC ExemptSolvents 5 Color Pigments 45 Corrosion Inhibitive Pigments 310 ExtenderPigments 74 Base Total: 1000

[0127] According to the present invention, direct to metal coatings andenhanced direct to metal coatings were prepared with the baseformulations described herein. The coating compositions also included anisocyanate catalyst, that is, a two-part formulation, such as isocyanatesolution 97GY088CAT, available from Deft Inc., having offices in Irvine,Calif. The direct to metal coatings and enhanced direct to metalcoatings, shown herein by way of exemple, were prepared by adequatelystirring appropriate amounts of isocyanate catalyst into the baseformulations described above. The amount of isocyanate catalyst includedin the coating compositions was added according to the amountrecommended by the supplier to ensure proper curing and cross-linking ofthe resulting coating. The solvent employed in the preparation of thecoating system of the present invention was chosen in such a manner asto facilitate the preparation of the coating mixture, to providesuitable application properties, and to provide an environmentallyacceptable paint.

[0128] Once the base and isocyanate catalyst were mixed together, thedirect to metal coatings and enhanced direct to metal coatings weresubstrates. Tests were run on various sample formulations, according toASTM B117 procedure, for either 1000, 2000, or 3000 hours. The resultswere evaluated according to the Keller Corrosion Rating Scale. Examplesof coating formulations that were prepared and Evaluated are providedbelow.

[0129] Test Procedure

[0130] The coating compositions tested were sprayed onto different metalsubstrates and allowed to dry (cure) naturally over time, typicallyabout one week. Edges and backs of samples were taped and front surfaceswere scribed with an “X” Pattern according to ASTM B117 procedure.Results are shown in Tables 5-7. TABLE 5 Non-chromium InhibitorContaining Primer Plus Topcoat. **Weight Percent Corrosion 2000 HourSample Inhibitor in Salt Fog Number *Deft Primer *Deft Topcoat TopcoatRating 396 44GY030 99GY001 None 3.6 397 44GY030 99GY001 9% Pr₆O₁₁ 3.6421 44GY030 99W009 None 3.5 386 44GY030 99W009 9% Pr₂O₃ 3.6 401 44GY03099W009 9% CeO₂ 3.6 399 44BK016 99GY001 9% Pr₆O₁₁ 3.4

[0131] TABLE 6 Self-priming Topcoat Formulations. 2000 **Weight PercentHours Salt Sample Weight Percent Inhibitor in Fog Number *Deft PrimerExtender Topcoat Rating A-5-A 03W211 44 CaSO₄.2H₂O 8% Pr₂O₃ 3.5

[0132] TABLE 7 Enhanced Self-priming Topcoat Formulations. **Corrosion2000 Hr Sample *Deft Inhibitor/Weight **Color Pigment/Weight***Extender/ Salt Fog Number Coating Percent Percent Weight PercentRating 139-057(A) 97GY088 Pr₂O₃ 12.89 Titanium Dioxide 13.89 Lo-Vel ®25.17 1A CaSO₄.2H₂O 47.74 Iron Yellow Oxide 0.17 HSF Carbazole Violet0.01 Phthalo Blue 0.03 139-059(A) 97GY089 Pr₂O₃ 2.14 Titanium Dioxide13.26 Lo-Vel ® 24.01 1A CaSO₄.2H₂O 42.45 Iron Yellow Oxide 0.18 HSFPr₂(SO₄)₃ 0.85 Carbon Black 0.10 Pr₆O₁₁ 16.98 Phthalo Blue 0.03139-058(A) 97GY089 Pr₆O₁₁ 23.62 Titanium Dioxide 12.83 Lo-Vel ® 23.23 2ACaSO₄.2H₂O 40.03 Iron Yellow Oxide 0.16 HSF Carbazole Violet 0.09Phthalo Blue 0.03 148-079(A) 97GY089 Pr₂O₃ 2.49 Titanium Dioxide 10.25Lo-Vel ® 17.48 1A CaSO₄.2H₂O 48.97 Iron Yellow Oxide 0.13 HSF Pr₂(SO₄)₃0.99 Carbazole Violet 0.01 Pr₆O₁₁ 19.58 Carbon Black 0.07 Phthalo Blue0.03 148-097(A) 97GY128 Pr₂O₃ 1.54 Titanium Dioxide 18.85 Lo-Vel ® 35.693A CaSO₄.2H₂O 30.63 Iron Yellow Oxide 0.24 HSF Pr₂(SO₄)₃ 0.61 CarbazoleViolet 0.01 Pr₆O₁₁ 12.25 Carbon Black 0.13 Phthalo Blue 0.05 148-078(A)97GY121 Pr₂O₃ 14.98 Titanium Dioxide 10.82 Lo-Vel ® 18.47 1A CaSO₄.2H₂O55.48 Iron Yellow Oxide 0.14 HSF Carbazole Violet 0.01 Carbon Black 0.07Phthalo Blue 0.03 148-084(A) 97GY124 Pr₂O₃ 2.14 Titanium Dioxide 19.45Lo-Vel ® 36.85 3A CaSO₄.2H₂O 42.45 Iron Yellow Oxide 0.24 HSF Pr₂(SO₄)₃0.85 Carbazole Violet 0.01 Pr₆O₁₁ 16.98 Carbon Black 0.13 Phthalo Blue0.05

[0133] As shown in Tables 5-7, incorporating extenders in conjunctionrare earth corrosion inhibitors into the enhanced self-priming topcoatresults in coating compositions with good or excellent performance. Asshown in Table 7, the extenders in conjunction with the rare earthcorrosion inhibitors when incorporated into the enhanced self-primingtopcoat, provides the best corrosion resistance. As shown in Table 5,incorporating corrosion inhibitors directly into a topcoat and applyingover a non-chrome primer, results in coating systems that do not performas well as the coatings shown in Table 7. As shown in Table 6, thecorrosion resistance of the self-priming topcoat with extenders and rareearth compound corrosion inhibitors is comparable to the perfomance ofthe non-chrome primer and topcoat formulations shown in Table 5. Thus,the self-priming topcoat compositions, according to the presentinvention, can achieve similar performance to systems that use both anon-chrome primer and a topcoat, without the use of a primer. Further,as shown in Table 7, the enhanced self-priming topcoats perform betterthan the non-chrome primer plus topcoat systems, thus providing bettercorrosion protection as a one-coat system without the need for ainter-coat polymeric coating or primer.

[0134] Accordingly, the enhanced self-priming topcoats have bothexcellent weathering resistance and durability, as well as the corrosionresistance necessary to provide protection to underlying substrates.

[0135] Further, the coating compositions according to the presentinvention are non-chromium containing and are environmentally superiorto currently known chromium containing coating systems. Finally theself-priming topcoat and enhanced self-priming topcoat compositionsprovide corrosion protection as a one-coat system without the need foran inter-coat polymeric coating or primer, thus minimizing theproduction time and costs of producing industrial, consumer, andmilitary parts and goods.

CONCLUSION

[0136] Controlling the local environment near the primer and substrateinterface is known to be important for maximum corrosion protection.Local pH and ionic activity can be modified in a favorable way byincorporating the various components described herein in the coating,including neutral to slightly acidic generating extenders, generatingacidic extenders and/or rare earth compounds, alone or in combinationwith each other and/or with other materials such as polymeric resinbinders, ionic exchange resins, and so forth. The coating compositionsdescribed herein have good adhesion to substrates such as metals,including aluminum and aluminum alloys. These novel coatings, coatingsystems and associated processes provide viable alternatives to coatingscontaining chromates as they are environmentally superior to currentlyknow chromium containing coating systems.

[0137] All publications, patents and patent applications areincorporated herein by reference. While in the foregoing specification,this invention has been described in relation to certain preferredembodiments thereof, and many details have been set forth for purposesof illustration, it will be apparent to those skilled in the art thatthe invention is susceptible to additional embodiments and that certainof the details herein can be varied considerably without departing fromthe basic principles of the invention. Therefore, it is manifestlyintended that this invention be limited only by the claims and theequivalents thereof.

1. A corrosion inhibiting coating composition comprising: a rare earthcompound; and a binder.
 2. The composition of claim 1 wherein the rareearth compound is selected from the group consisting of rare earthoxides, mixed oxides, solid solution oxides, hydroxides, hydratedoxides, salts, triflates, complexes and combinations thereof.
 3. Thecomposition of claim 2 wherein the rare earth compound is anhydrous orhydrated.
 4. The composition of claim 1 wherein the rare earth compoundcomprises one or more metal cations selected from the group consistingof praseodymium, terbium, cerium, samarium, ytterbium, yttrium,neodymium and combinations thereof.
 5. The composition of claim 1wherein the rare earth compound is selected from the group consisting ofcerium oxide, cerium hydroxide, cerium solid solution mixed oxide,cerium oxide mixture, cerium salt, neodymium oxide, neodymium hydroxide,neodymium solid solution mixed oxide, neodymium oxide mixture, neodymiumsalt, praseodymium oxide, praseodymium hydroxide, praseodymium solidsolution mixed oxide, praseodymium oxide mixture, praseodymium salt,ytterbium oxide, ytterbium hydroxide, ytterbium solid solution mixedoxide, ytterbium oxide mixture, ytterbium salt, yttrium oxide, yttriumhydroxide, yttrium solid solution mixed oxide, yttrium oxide mixture,yttrium salt, terbium oxide, terbium hydroxide, terbium solid solutionmixed oxide, terbium oxide misture, terbium salt, and combinationsthereof.
 6. The composition of claim 1 wherein the rare earth compoundis a praseodymium compound.
 7. The composition of claim 6 wherein thepraseodymium compound is selected from the group consisting ofpraseodymium(III), praseodymium(III/IV), praseodymium(IV) compounds andmixtures thereof.
 8. The composition of claim 6 wherein the praseodymiumcompound is a praseodymium(III) compound.
 9. The composition of claim 8wherein the praseodymium(III) compound is a praseodymium(III) oxide. 10.The composition of claim 6 wherein the praseodymium compound is apraseodymium(III/IV) compound.
 11. The composition of claim 10 whereinthe praseodymium(III/IV) compound is a praseodymium(III/IV) oxide. 12.The composition of claim 6 wherein the praseodymium compound is apraseodymium(IV) compound.
 13. The composition of claim 1 comprisingabout 0.1 to about 90 wt % Pr₆O₁₁.
 14. The composition of claim 1comprising about 0.1 to about 28 wt % Pr₆O₁₁.
 15. The composition ofclaim 1 further comprising one or more neutral to slightly acidicgenerating extenders or one or more acidic generating extenders.
 16. Thecomposition of claim 15 wherein the one or more neutral to slightlyacidic generating extenders or one or more acidic generating extendersis a sulfur, phosphorus or silicon oxyanion-containing salt.
 17. Thecomposition of claim 1 wherein the composition is selected from thegroup consisting of aqueous, solvent-based, and powder coatingcompositions.
 18. The composition of claim 1 wherein the composition isan aqueous composition.
 19. The composition of claim 2 wherein thebinder is an organic polymer selected from the group consisting ofepoxy, urethane, urea, acrylate, alkyd, melamine, polyester, vinyl,vinyl ester, silicone, siloxane, silicate, sulfide, sulfone, epoxynovolac, epoxy phenolic, amides, drying oils, and hydrocarbon polymers.20. The composition of claim 2 wherein the binder is an epoxy polymer.21. The composition of claim 2 in combination with a material selectedfrom the group consisting of linear and cyclic dextrins, triflic acid,triflates, acetates, talc, kaolin, organic-based ion exchange resins,and combinations thereof.
 22. The composition of claim 21 comprisingabout 0.03 to about 5 wt % cyclodextrin, about 0.1 to about 0.5 wt %triflic acid, or about 0.1 to about 5 wt % ionic exchange resin.
 23. Thecomposition of claim 2 further comprising a material selected from thegroup consisting of gelatin and gelatin derivatives.
 24. The compositionof claim 23 comprising about 0.03 to about 5 wt % gelatin.
 25. Thecomposition of claim 2 further comprising a material selected from thegroup consisting of amino acids, amino acid derivatives and combinationsthereof.
 26. The composition of claim 25 wherein the amino acid isselected from the group consisting of glycine, arginine, and methionine.27. The composition of claim 25 wherein the amino acid derivative ismethionine sulfoxide or methionine methyl sulfoxide.
 28. The compositionof claim 22 comprising about 0.1 to about 5 wt % amino acid.
 29. Thecomposition of claim 1 wherein the rare earth compound is a rare earthcarbonate or a rare earth triflate.
 30. The composition of claim 2further comprising a coloring pigment.
 31. The composition of claim 30wherein the coloring pigment is TiO₂.
 32. A substrate coated with thecomposition of claim
 1. 33. The substrate of claim 32 wherein thesubstrate is selected from the group consisting of aluminum, aluminumalloys, steel, galvanized steel, zinc, zinc alloys, magnesium, andmagnesium alloys.
 34. The substrate of claim 32 wherein the substrate isaluminum.
 35. A corrosion inhibiting composition comprising: a rareearth compound; a binder; and a neutral to slightly acidic generatingextender or an acidic generating extender.
 36. The composition of claim35 wherein the neutral to slightly acidic generating extender or theacidic generating extender is a sulfur, phosphorus or siliconoxyanion-containing salt.
 37. The composition of claim 35 wherein theneutral to slightly acidic generating extender or the acidic generatingextender is an anhydrous or hydrous lanthanide sulfate.
 38. Thecomposition of claim 138 wherein the metal sulfate is selected from thegroup consisting of anhydrous magnesium sulfate, hydrous magnesiumsulfate, anhydrous calcium sulfate, hydrous calcium sulfate, bariumsulfate, samarium sulfate, and strontium sulfate.
 39. The composition ofclaim 138 wherein the metal sulfate is hydrous calcium sulfate,anhydrous calcium sulfate or strontium sulfate.
 40. The composition ofclaim 38 comprising about 1 to about 99 wt % metal sulfate.
 41. Thecomposition of claim 38 comprising about 45 to about 75 wt % metalsulfate.
 42. The composition of claim 36 wherein the rare earth compoundis selected from the group consisting of rare earth oxides, hydroxides,mixed oxides, solid solution oxides, hydrated oxides, salts, triflates,complexes, and combinations thereof.
 43. The composition of claim 36wherein the rare earth compound comprises one or more metal cationsselected from the group consisting of praseodymium, terbium, cerium,samarium, ytterbium, yttrium, neodymium and combinations thereof. 44.The composition of claim 36 wherein the rare earth compound is apraseodymium compound.
 45. The composition of claim 44 wherein thepraseodymium compound is selected from the group consisting ofpraseodymium(III), praseodymium(III/IV), praseodymium(IV) compounds andcombinations thereof.
 46. The composition of claim 44 wherein thepraseodymium compound is a praseodymium(III) compound.
 47. The coatingcomposition of claim 44 wherein the praseodymium compound is apraseodymium(III) sulfate or a praseodymium(III/IV) oxide.
 48. Thecomposition of claim 44 wherein the praseodymium compound is apraseodymium(III/IV) compound.
 49. The composition of claim 44 whereinthe praseodymium compound is a praseodymium(IV) compound.
 50. Thecomposition of claim 43 wherein the composition is selected from thegroup consisting of aqueous, solvent-based, and powder coatingcompositions.
 51. The composition of claim 43 wherein the binder is anorganic polymer selected from the group consisting of epoxy, urethane,urea, acrylate, alkyd, melamine, polyester, vinyl, vinyl ester,silicone, siloxane, silicate, sulfide, sulfone, polysulfide, epoxynovolac, epoxy phenolic, amides, drying oils, and hydrocarbon polymers.52. The composition of claim 43 wherein the binder is an epoxy polymer.53. The composition of claim 43 wherein the binder is an inorganicpolymer selected from the group consisting of silicone, siloxane andsilicate polymers.
 54. The composition of claim 43 further comprising acoloring pigment.
 55. The composition of claim 54 wherein the coloringpigment is TiO₂.
 56. A corrosion inhibiting primer compositioncomprising: a praseodymium (III/IV) mixed oxide; and a binder.
 57. Thecomposition of claim 56 wherein the composition is selected from thegroup consisting of aqueous, solvent-based, and powder coatingcompositions.
 58. The composition of claim 56 wherein the binder is anorganic polymer selected from the group consisting of epoxy, urethane,urea, acrylate, alkyd, melamine, polyester, vinyl, vinyl ester,silicone, siloxane, silicate, sulfide, sulfone, polysulfide, epoxynovolac, epoxy phenolic, amides, drying oils, and hydrocarbon polymers.59. The composition of claim 56 wherein the binder is an epoxy polymer.60. The composition of claim 56 wherein the binder is an inorganicpolymer selected from the group consisting of silicone, siloxane andsilicate polymers.
 61. The composition of claim 56 further comprising acoloring pigment.
 62. The composition of claim 61 wherein the coloringpigment is TiO₂
 63. A corrosion inhibiting coating compositioncomprising: a binder; and a rare earth element mixed oxide comprisingtwo or more rare earth element oxides selected from the group consistingof oxides, mixed oxides, solid solution oxides, hydrated oxides andhydroxides.
 64. The composition of claim 63 wherein at least one of thetwo or more rare earth element oxides is selected from the groupconsisting of Y₂O₃; La₂O₃, CeO₂, Pr(OH)₃, PrO₂, Pr₂O₃, Pr₆O₁₁, Nd₂O₃,Sm₂O₃, Tb₄O₇, and Yb₂O₃.
 65. The composition of claim 63 wherein atleast one of the two or more rare earth element oxides is selected fromthe group consisting of PrO₂, Pr₂O₃, and Pr₆O₁₁.
 66. The composition ofclaim 63 further comprising a neutral to slightly acidic generatingextender or an acidic generating extender.
 67. A corrosion inhibitingcoating composition comprising: a binder; and one or more rare earthelement oxides selected from the group consisting of oxides, mixedoxides, solid solution oxides, hydrated oxides and hydroxides.
 68. Thecomposition of claim 139 wherein the rare earth praseodymium oxide isselected from the group consisting of PrO₂, Pr₂O₃, and Pr₆O₁₁.
 69. Thecomposition of claim 67 further comprising a neutral to slightly acidicgenerating extender or an acidic generating extender.
 70. A corrosioninhibiting coating composition having a local pH or ionic activitycomprising: a binder; one or more rare earth element oxides selectedfrom the group consisting of oxides, mixed oxides, solid solution oxidesand hydroxides, wherein at least one of the one or more rare earthelement oxides is an anhydrous praseodymium oxide; and a metal sulfate.71. A corrosion inhibiting coating composition comprising: an effectivecorrosion inhibiting amount of one or more neutral to slightly acidicgenerating extenders or acidic generating extenders; and a binder. 72.The composition of claim 71 wherein the binder is an organic polymerselected from the group consisting of epoxy, urethane, urea, acrylate,alkyd, melamine, polyester, vinyl, vinyl ester, silicone, siloxane,silicate, sulfide, sulfone, polysulfide, epoxy novolac, epoxy phenolic,amides, drying oils, and hydrocarbon polymers.
 73. The composition ofclaim 71 wherein the binder is an epoxy polymer.
 74. The composition ofclaim 71 wherein the binder is an inorganic polymer selected from thegroup consisting of silicone, siloxane and silicate polymers. 75.(Canceled)
 76. The composition of claim 71 further comprising one ormore color pigments.
 77. The composition of claim 76 wherein one of theone or more color pigments is TiO₂.
 78. The composition of claim 71wherein at least one of the one or more neutral to slightly acidicgenerating extenders or acidic generating extenders is a sulfur,phosphorus or silicon oxyanion-containing salt.
 79. The composition ofclaim 78 wherein the sulfur, phosphorus or silicon oxyanion-containingsalt is selected from the group consisting of a metal cation sulfate, ametal cation sulfite, a metal cation sulfonate, a metal cationprotonated phosphate, a cation phosphate, a metal cation phosphonite, anoxyphosphate, a clay mineral kaolin and combinations thereof.
 80. Thecomposition of claim 71 wherein the one or more neutral to slightlyacidic generating extenders or acidic generating extenders are added ata weight percent of about 100% of total extender content.
 81. Thecomposition of claim 71 further comprising other components selectedfrom the group consisting of linear and cyclic dextrins, triflic acid,triflates, acetates, talc, kaolin, organic-based ion exchange resins,and combinations thereof.
 82. The composition of claim 71 furthercomprising gelatin, gelatin derivatives, and combinations thereof. 83.The composition of claim 71 further comprising amino acids, derivativesof amino acids, and combinations thereof.
 84. A substrate coated withthe composition of claim
 71. 85. The substrate of claim 84 wherein thesubstrate is selected from the group consisting of aluminum, aluminumalloys, steel, galvanized steel, zinc, zinc alloys, magnesium, magnesiumalloys and composites.
 86. The substrate of claim 84 wherein thesubstrate is aluminum.
 87. A corrosion inhibiting compositioncomprising: an effective corrosion-inhibiting amount of a neutral toslightly acidic generating extender or an acidic generating extenderhaving a metal cation selected from the group consisting of calcium,strontium, and barium; and a binder.
 88. The composition of claim 87wherein the binder is an organic polymer.
 89. The composition of claim88 wherein the organic polymer is selected from a group consisting ofepoxy, urethane, urea, acrylate, alkyd, melamine, polyester, vinyl,vinyl ester, silicone, siloxane, silicate, sulfide, sulfone, epoxynovolac, epoxy phenolic, amides, drying oils, hydrocarbon polymers andcombinations thereof.
 90. The composition of claim 87 wherein the binderis an inorganic polymer.
 91. The composition of claim 90 wherein theinorganic polymer is selected from a group consisting of silicates,silicones, silicate polymers, and combinations thereof.
 92. Thecomposition of claim 87 wherein the neutral to slightly acidicgenerating extender or acidic generating extender is selected from thegroup consisting of metal cation sulfates, metal cation phosphates,metal cation silicates, and combinations thereof.
 93. The composition ofclaim 87 wherein the neutral to slightly acidic generating extender oracidic generating extender comprises a metal cation selected from thegroup consisting of yttrium, a lanthanide, and combinations thereof. 94.The composition of claim 87 wherein the neutral to slightly acidicgenerating extender or the acidic generating extender is a metalsulfate.
 95. The composition of 87 wherein the neutral to slightlyacidic generating extender or acidic generating extender is added in aweight percent of about 100% of total extender content.
 96. Thecomposition of claim 87 further comprising other components selectedfrom the group consisting of linear and cyclic dextrins, triflic acid,triflates, acetates, talc, kaolin, organic-based ion exchange resins,and combinations thereof.
 97. The composition of claim 87 furthercomprising gelatin, gelatin derivatives, and combinations thereof. 98.The composition of claim 87 further comprising amino acids, derivativesof amino acids and combinations thereof.
 99. A coating systemcomprising: a coating containing an effective corrosion-inhibitingamount of one or more rare earth compounds, one or more neutral toslightly acidic generating extenders or one or more acidic generatingextenders applied to a substrate.
 100. The coating system of claim 99further comprising one or more pretreatment coatings applied to thesubstrate to form a pretreated substrate and a topcoat.
 101. The coatingsystem of claim 100 wherein the topcoat is a urethane topcoat.
 102. Thecoating system of claim 99 wherein the coating system is a resin system.103. The coating system of claim 99 wherein the coating system isselected from the group consisting of a UV-coating system, electrolyticcoating system, appliqué, powder coating system, and microwave coatingsystem.
 104. The coating system of claim 99 wherein the substrate iscoated by a method selected from the group consisting of spraying,brushing, rolling and dipping.
 105. The coating system of claim 99wherein the substrate is a composite substrate.
 106. The coating systemof claim 99 wherein the substrate is selected from the group consistingof aluminum, aluminum alloys, steel, galvanized steel, zinc, zincalloys, magnesium, and magnesium alloys.
 107. A coating systemcomprising: one or more pretreatment coatings applied to a substrate toform a pretreated substrate; and a coating containing an effectivecorrosion-inhibiting amount of a corrosion-inhibiting carbon pigmentcombined with a neutral to slightly acidic generating extender or anacidic generating extender, the coating applied to the pretreatedsubstrate.
 108. The coating system of claim 107 further including aurethane topcoat.
 109. The coating system of claim 106 wherein thecoating system is selected from the group consisting of a UV-coatingsystem, electrolytic coating system, appliqué, powder coating system,and microwave coating system.
 110. The coating system of claim 106wherein the pretreated substrate is coated by a method selected from thegroup consisting of spraying, brushing, rolling and dipping.
 111. Acoating system comprising: One or more pretreatment coatings applied toa substrate to form a pretreated substrate; and a coating containing aneffective corrosion-inhibiting amount of one or more rare earthcompounds, one or more neutral to slightly acidic generating extendersor one or more acidic generating extenders; and at least one or moreother components, the coating applied to the pretreated substrate. 112.The coating system of claim 111 further including a urethane topcoat.113. The coating system of claim 111 wherein the coating system is aresin system.
 114. The coating system of claim 111 wherein the coatingsystem is selected from the group consisting of a UV-coating system,electrolytic coating system, appliqué, powder coating system, andmicrowave coating system.
 115. The coating system of claim 111 whereinthe pretreated substrate is coated by a method selected from the groupconsisting of spraying, brushing, rolling and dipping.
 116. The coatingsystem of claim 111 wherein the pretreated substrate is a compositesubstrate.
 117. A method for coating a substrate with a compositioncomprising treating the substrate with the composition of claim 1, andcuring the applied composition.
 118. A method for coating a substratecomprising treating the substrate with a conversion coating, applyingthe composition of claim 1, and curing the applied composition.
 119. Themethod of claim 118 wherein the conversion coating is selected from thegroup consisting of cerium conversion coatings, praseodymium conversioncoatings, phosphate conversion coatings, zinc-type conversion coatings,and chromium conversion coatings and anodized-type coatings.
 120. Themethod of claim 118 wherein the conversion coating is a chromiumconversion coating.
 121. A method for preparing a coating compositioncomprising: preparing a paint formulation; and adding an effectivecorrosion-inhibiting amount of a rare earth compound, a neutral toslightly acidic generating extender or an acidic generating extender tothe paint formulation to produce a coating composition.
 122. The methodof claim 121 further comprising pre-dispersing the rare earth compound,the neutral to slightly acidic generating extender or acidic generatingextender with a dispersant.
 123. A method comprising: providing asubstrate to be coated; and coating the substrate with a coatingcomposition having an effective corrosion-inhibiting amount of a rareearth compound, a neutral to slightly acidic generating extender or anacidic generating extender.
 124. The method of claim 123 wherein thesubstrate is a pretreated substrate.
 125. The method of claim 124wherein the pretreated substrate is coated by a method selected from thegroup consisting of spraying, brushing, rolling and dipping.
 126. Themethod of claim 123 further comprising applying a topcoat.
 127. Thecomposition of claim 15 wherein at least one of the one or more neutralto slightly acidic generating extenders or one or more acidic generatingextenders is a sulfur, phosphorus or silicon oxyanion-containing salt.128. The composition of claim 15 wherein at least one of the one or moreneutral to slightly acidic generating extenders or one or more acidicgenerating extenders is a sulfate.
 129. The composition of claim 128wherein the sulfate is a metal sulfate.
 130. The composition of claim129 wherein the metal sulfate is selected from the group consisting ofcalcium sulfate, strontium sulfate, magnesium sulfate, barium sulfateand combinations thereof.
 131. The composition of claim 15 wherein atleast one of the one or more neutral to slightly acidic generatingextenders or one or more acidic generating extenders is a phosphate.132. The composition of claim 44 wherein the praseodymium compound is apraseodymium(III) sulfate or a praseodymium(III/IV) oxide.
 133. Thecomposition of claim 66 wherein the extender is substantially soluble.134-135. (Canceled).
 136. The coating system of claim 106 wherein thecoating system is a resin system.
 137. The composition of claim 128wherein the sulfate is a praseodymium sulfate.
 138. The composition ofclaim 35 wherein the neutral to slightly acidic generating extender oran acidic generating extender is a metal sulfate.
 139. The compositionof claim 63 wherein at least one of the one or more rare earth elementoxides is a rare earth praseodymium oxide or a rare earth terbium oxide.140. The substrate of claim 85 wherein the composite is a carbon fibercomposite